What is the QuickBooks TLG File?

Written by Charlie Russell

When you create a company in QuickBooks there will be several files created. One has a file type of “QBW” – that is your actual company data file. Another that is created has a file type of “TLG”, and that is the source of some confusion as well as some misunderstandings. Let’s review a few facts about this file.

What the TLG File Contains

As you use your QuickBooks company file it is being updated with the transactions that you enter. In addition to updating the company file, QuickBooks will save information about the transactions in the TLG or Transaction Log file. QuickBooks is tracking all of the changes that you make to your company file. The TLG file continues to grow, and it isn’t unusual to see the TLG file become bigger than the QBW file.

I’m told by some people that as the TLG file grows you may see some decrease in system performance, at least when the file gets very large. I’ve not been able to confirm that myself. The increased file size certainly can impact performance and possibly cost of backup programs and procedures.

imageAs a side note, you may also see a file with an ND file type – this is the NetConnect file, containing information that relates to multi user access to your company file. You should not erase it.

What Use is the TLG File?

In your normal day-to-day operation of QuickBooks, the TLG file is of no use to you. You don’t have a way to look at it, your use of QuickBooks won’t be affected by its presence. So what is its value to you?

The value of the TLG file is for data restoration. If your company file is erased or damaged, the TLG file can be used in conjunction with your most recent backup to restore transactions that were entered since that backup. Let me give you a simplified example.

  1. You have an inventory item that has an on-hand quantity of 10.
  2. You make a backup copy of your company file (more on this later).
  3. You receive 20 more of that item.
  4. For some reason your company file is damaged, but you still have the current TLG file and your backup file.
  5. You restore the backup, now you are back to an on-hand quantity of 10.
  6. The transaction log is applied to your restored backup, it gets you back to 20 on-hand.

Sounds simple? Unfortunately it isn’t. You cannot apply the transaction log, only certain businesses can.

Who Can Restore a TLG File?

There is no user-accessible utility program that will let you take a backup file and update it with the transaction log. Some options that you have are:

  • QuickBooks Data Services (Intuit QuickBooks Support): Their web site is a bit vague, it is not clear if these fees apply to applying a transaction log to a backup. Their data recovery service comes in two flavors, “standard” at $250 with your project being added to the queue (I’ve heard it can be multiple days or more) and “express” at $750 where you go to the top of the queue. There is a nonrefundable analysis fee.
  • AccountingUsers, Inc: They advertise a standard service ($275 for two business days) and expedited service ($450 overnight). No fee if they are not successful. http://quickbooksusers.com/datarepair.htm
  • QB or not QB: At this time I’m not sure what their fee is, most likely it will be variable depending on the size of your file and how quickly you want it turned around. http://www.qbornotqb.com/

Each of these services have a cost – a fee that you will have to pay, and a turnaround time during which you cannot use your QuickBooks company file to add or change ANY information.

Note that I have not used any of these services for this kind of recovery. I’ve spoken with the people at AccountingUsers Inc and QB or Not QB on multiple occasions, and they sound like reasonable people with the appropriate technical knowledge, but I haven’t tested the services.

Why Not Just Delete It?

OK, we’ve established that the file gets large and takes up space (particularly if you are copying backups and this file to a CD or other media), that it might slow down performance as it gets larger, and that you have to pay money to be able to use it to recover data. Why bother with it? Can’t I just delete it?

If you have been reading my blog for long you will know that I am a bit hyper about data security and backups. So, do we need the file? On one hand, if you have a good backup plan, you are making regular backups in several ways, and if a disaster occurs you can restore your backups with a minimum of fuss. No need for the TLG file?

Well, I don’t agree with that. I believe that you have to take advantage of every opportunity for data security that you possibly can. That means that you should be using the QuickBooks backup feature, and including the TLG file in your set of files that are backed up daily (or at least very often). It adds one more level of safety to your backup plan, in case you run into an odd situation. Sometimes, for example, you can have damaged data in your QBW file that just cannot be fixed. The damage may not be noticeable right away, so your daily backups might also be corrupted. A good QBB backup and matching TLG file may be what you need to get back to the point before the damage occurred, and then move forward to your current state.

Note that if you delete the TLG file, QuickBooks will just start another, but it will have limited use as it is incomplete.

Managing QuickBooks Backups and the TLG File

The general concept for managing backups and TLG files is that when you make a backup using the QuickBooks backup feature (from the File menu), QuickBooks will create a file with a QBB file type and clear out the TLG file. The backup has all the transactions saved, so you don’t need that transaction log. From that point on the TLG file will grow again, holding all transactions since that backup.

However, not all backup files are equal. QuickBooks will only delete the TLG file if you make a manual backup with the verify option on.

QuickBooks backup options

If you do not select the complete verification, the TLG file is not cleared and your QBB file cannot be used with that TLG file. In addition, this must be a manual backup, selecting backup from the File menu. A scheduled backup will not perform this function, even if complete verification is selected. QuickBooks Online Backups, or backups that you make yourself with your own backup programs, also won’t work.

The TLG file and your company file must match. You cannot use it, for example, to “merge” transactions from another computer (such as your home laptop, to merge to your office workstation). If you copy a TLG from your laptop back to your office computer, QuickBooks will see that they don’t match and will “reset” the TLG file, lose all saved transactions in the log.

I should note also that making a portable company file has no affect on your TLG file – BUT if you RESTORE a portable company file, it won’t match the TLG file and the TLG file will be reset.

Here is a company file (fairly small) and a TLG file before making the backup:

TLG before backup Here are the files after a manual backup with the verify option on.

TLG after backup So, my recommendations are:

  • DO NOT delete the TLG file if at all possible.
  • PERIODICALLY run a manual QuickBooks backup and save the QBB file
  • INCLUDE the TLG file in your daily backup routine.

About the author

Charlie Russell

Charlie Russell has been involved with the small business software industry since the mid 70's, and remembers releasing his first commercial accounting software product when you had an 8-bit microcomputer with one 8 inch floppy disk drive. He has a special interest in inventory and manufacturing software for small businesses. Charlie is a Certified Advanced QuickBooks ProAdvisor with additional certifications for QuickBooks Online and QuickBooks Enterprise, as well as being a Xero Certified Partner. Charlie started blogging about QuickBooks in 2008 (Practical QuickBooks) and has been writing for the Accountex Report (formerly the Sleeter Report) since 2011. He retired from accounting and QuickBooks activities in early 2018.

Visit his CCRSoftware web site for information about his QuickBooks add-on products. He is also the author of the California Wildflower Hikes blog.


  • I have a 2011 database and have done manual, full verify backups and my TLG file is still around a Gig in size. (The QBQ is around 270MB) Any suggestions? The log file folder is over 4.2 Gig. Using lates build. Very annoying.

  • Robert, if the TLG file isn’t shrinking when you do the backup, you may be missing something. Try running the backup from the machine that is the database server.

    Also, there is a lot of talk going around about the new “search” function in the 2011 version possibly making the TLG file build to crazy sizes. I haven’t confirmed that myself. Turning off the search function might be something to consider. Again, I haven’t confirmed this myself so I’ve not written an article about it.

  • Robert, you might also try copying your company file and .TLG file to the fastest machine on your network with your QB program installed on it and try doing a manual backup there.

    Don’t forget to make sure if you are in a networked environment to confirm that all your QB programs are running the same versions. One of my Seattle clients had this problem.

  • My TLG file is 35 gigs, lol. We do a complete system back up rather then QB back up. No wonder why system backups are taking 4 hours. Good thing i started digging who knows how much bigger this is going to get. If QB BACKUP doesn’t get rid of this monstrosity i’m deleting it. Using Enterprise 2011.

  • Seems like turning off the automatic Search updating feature has solved this for us. After a successful full verification backup, I deleted the TLG file and it has stay at around 576KB over the last several hours of QB usage.

    • Robert, I’ve seen several reports that say that. I’ve not had time to investigate that, and I’m not getting any response to my queries about this at Intuit. I didn’t see anything referring to the issue in the recent 2011 R6 update, either.

  • Our 2003 Microsoft Server has crashed and I cannot obtain nor open my Quickbook files. However I do have a TLG file. How can I (if possible move the contents of this file to my Company File. I’m desperate.

  • I have found that sometimes on the UK 2008 / US2007 version of QuickBooks, that running a manual backup does not clear the TLG file.

    However, i found that by creating a portable backup, and then restoring the from the portable backup clears the TLG.

  • Hey Charlie, thanks for the articles.

    I’ve taken on a client that has “never” used the QB backup function and has a very large TLG file. it all running very slowly. Problem is I cant run backup even without data checking QB stops responding at 99% (don’t you love that ?) Nuts and bolts fine it’s all local files and apps whilst doing this stuff. So here’s my real question. (We have copies of both qbw and tlg files)

    Q: Is QB using the contents of the TLG file on a daily basis to render transaction info to the main database. In other words if I do delete the current one will I suddenly not have some transactions or entries ?(I understand about the data recovery thing)

    QBW is 693,000 KB TLG is 4,383,000 KB

    Ta all for input , I’m burning too many hours here looking for a result.

    • You can delete the TLG file without harming the normal day-to-day use of QB. It is there for certain kinds of disaster recovery situations – but odds are you won’t use it (few people do) and if you don’t have a valid backup that matches the creation of the TLG initially, the TLG is pretty much worthless now.

      If you can’t do a backup, start by doing a “file recovery” and then examine the QBWIN.LOG file for error messages.

  • Since I upgraded from pro 2013 to premier 2014 my QBW file has been staying at the same 285.172MB in size.
    In the last 3 months we have added 100’s of transactions and it does get larger but after a backup, verify or switch to single user mode it reverts back to 285.172MB in size.

    The only anomaly I see is the new TLG file is not the 2014.QBW.TLG I expected it to be after the conversion from 2013.QBW to 2014.QBW
    It is still 2013.QBW.TLG

    I realize my QBW file is large but I have run up to 350MB files sizes on this server (Shared folder on server)-(2 work Stations) setup many times in the past without problems.

    Although I don’t appear to be losing data I need to understand this weird behavior.
    Why is my TLG file the wrong name and why does my QBW file not get larger?
    File verifies OK
    All machines are running Win7 with full updates.

    • You renamed the QBW file? And there isn’t a matching TLG file with the same name? That doesn’t sound right.

      Are you sure you are using that specific QBW file and not another one in a different location? Open the file, press F2, confirm the location of the file that you opened.

      • So far so good I seem to have solved the TLG issue.

        Now the Million Dollar question now is why isn’t the 2014.QBW file increasing in size?
        Is there something in the 2014 setup I am not aware of or is this normal behaviour for 2014?

        QB 2014 Premier-Wholesale.
        Dedicated server/Win7 Business hosting QB file.
        Two users accessing QB file running Win7 Home Premium.
        (QB 2013 PRO & QB 2014 Premier-Wholesale installed on these two desktop machines.)

        Rebuilt the server to eliminate all traces of QB 2013 Pro which was previously installed on the server. (Only installed the 2014 server engine)
        Copied existing 2014.QBW file to shared folder on server.
        (Accessed 2014.QBW from one of the work stations and a 2013.QBW.TLG file was created again!!!!)
        Copied 2014.QBW file to one of the workstation, opened it and WALLA a 2014.QBW.TLG file was created.
        Created a complete verify/backup of the 2014.QBW file and copied the 2014.QBB file to the server.
        Opened the 2014.QBB file on the server from a workstation and THEN the proper 2014.QBW.TLG file was created.
        (Or maybe it was just extracted from the backup file.)
        So far so good, this seems to have solved the TLG issue.
        After 2 days of data entry the 2014.QBW file increases in size to approximately 292,236 KB when it is being accessed but upon exiting QB on the work stations it returns to 285.172 KB which is the same size it’s been since QB 2014 Premier-Wholesale was installed 2 months ago.
        (TLG file does increase in size and stays there.)
        The “F2” “Product Information” screen indicates QB is doing what it’s supposed to as it shows a daily increase in:
        Files Size:
        Total Transactions:
        Total Targets:
        File Fragments: They remain in the single digit range
        All othe values appear to be correct.

        “List Imformation” values appear to be correct.

        None of the other QB files on the server or the workstations are changing size.

        Need to recheck the QBWIN.LOG file for errors but I don’t expect to find any.

        Any idea as to why the 2014.QBW file stays the same size?

        I’m revisiting tomorrow PM for another troubleshooting session.

        Thanks, Lucien

        • I can’t give you concrete answers without looking at your system directly. If you wish to have an expert dig into things then I can refer you to some excellent people.

          Some things to keep in mind:
          1) There is no major change between QuickBooks 2014 and prior years in this regard (unless you are comparing to 2005 and older versions). Intuit is always working on improving efficiency, so there can be minor changes from year to year, but not major differences.

          2) If the number of transactions are increasing as you use the system, that is a good indication that all is well. There isn’t going to be a direct one-to-one relation to the number of transactions and the physical size of the file (either QBW or TLG). The file space can be allocated in chunks – a big chunk is allocated and then he program uses up that space over time. And if records are deleted in one of the compression procedures the physical size of the file may not decrease, just the space is opened up for future addition of records.

          3) If you are using a file compression feature in your system (Windows, or other compression systems) the file size you see in the F2 window most likely won’t directly relate to the physical size you see in Windows itself.

          4) The size of your data drive can also have some effect, as can the version of Windows you are using. The physical size of the allocated space from Windows will also grow in chunks, and then be internally consumed as your file grows. Older operating systems allocate different size chunks than newer operating systems. Larger size drives, like 1TB, will often allocate space in larger increments than smaller drives (and that can vary with version of Windows and settings from the manufacturer).

          If you are losing data, if information is disappearing or not being saved, I would be concerned. If the numbers in the F2 window (total transactions, total targets) are moving up as you use the product, I don’t see a problem.

  • I’m thinking this is part of the issue.
    This 285.172 file size is the size it was when I converted the 2013.QBW file to 2014.QBW back in March of this year.

    Thanks Lucien

  • Thanks Charlie,
    1) Good to know.

    2)is the only thing that makes sense.

    “The file space can be allocated in chunks – a big chunk is allocated and then he program uses up that space over time.”

    I knew QB allocated in chunks and I’ve seen it not increase for short periods before but never this long.
    Couple that with the TLG issue and I got concerned.
    Don’t want my client to lose data on my watch…..

    Once more “One is never to old to learn something” 🙂

    Your spot on reviews/articles have either saved my bacon or confirmed what I thought I knew several times in the past.

    You are appreciated!

    Thanks, Lucien

  • Following up, the final “vapor fix” appears to have been installing the OS & QB on a new hard drive. The “Total Targets” reset from 320K to 190K and after a few days of data entry the file size now grows as expected.

    There does not appear to have been any data loss to the company file and no other problems have surfaced since.

    After auditing the hardware I realized the original hard drive had been in use for over 4 years. I typically swap them out after 3 years just to avoid these kinds of issues. $30~ a year per machine is good ROI.
    I then re-format & verify the used drives for non critical purposes.

    Again, THANKS for all your articles and tips!


  • I am using QBooks 2009 and had computer problems in 2013. I discovered and keep discovering that data is missing from 2013. My bank recs are gone for a few months, although I have the print outs that they were done, then discovered my credit card statements entries have disappeared. I don’t have proof that these were done. Had to re-enter it all and now losing my job. It would be nice to have some kind of explanation. God and I know it was done, but some technical reasoning would sure be nice.

    • If you had “computer problems” of some sort, there can be all kinds of reasons why some data is missing. You may want to have someone take a look at the file. Also, make a backup, try the “rebuild” option to see if the file can be corrected.

  • […] What is the QuickBooks TLG File? – Sleeter Report – Robert, if the TLG file isn’t shrinking when you do the backup, you may be missing something. Try running the backup from the machine that is the database server. […]