LVL_ERROR--Error: Unable to read company file attributes - owner id = {xxxxxx...}

You should ask Data Service team to condense your file. Otherwise, consider to purchase a 3rd party condense service.

Hello there, Steverguy.

I recognize the importance of condensing your company file in QuickBooks Desktop. Let's perform the troubleshoot of data damages here in the QuickBooks. Allow me to guide you the two solutions. 

Solution 1: Rebuild and verify.

1. Rebuild data.
   1. To do this, go to File > Utilities > Rebuild Data.
   2. When prompted to back up the file, click OK.
   3. Once the message Rebuild has completed appears, click OK and proceed with the next step.
2. Verify data.
   1. Go to File > Utilities > Verify Data.
   2. When you see the message QuickBooks detected no problem with your data, click OK. You can now continue using the file.
   3. If after verifying, QuickBooks detected the same problem, perform the next solution.

Solution 2: Identify and manually edit the damaged item

1. Identify the item number using the QBWin.log.

1. While QuickBooks is open, press F2 to open the Product Information window.
2. Press F3 to open the Tech Help window and go to the Open File tab.
3. Under the Open File tab, look for QBWin.log then click Open.
4. Once QBWin.log is open, press CTRL + F to bring up the Find window and search for the error.
5. Take note of the item number in the error message.

2. Export your item list and identify the damaged item.

1. Go to File > Utilities > Export > Lists to IIF Files > Item List.
2. Choose a location you prefer and click Save.
3. Once saved, right-click the file and choose Open with Excel. (Or, open Excel and drag the file on to the spreadsheet).
4. Locate the REFNUM, which matches the item number in the error message, and note the name of the item.

3. Correct the item's quantity on hand (QOH).

1. In the Reports menu, under Inventory, select Inventory Valuation Detail.
2. Set the Date range to All.
3. Locate the item and find the date when its quantity first became negative.
4. You can either delete the "build assembly" that is involved with the negative on hand OR,
5. You can do an Inventory Adjustment to increase the quantity of the item.

4. Verify your file again. To ensure that the data issue is resolved, verify your company file again by going to File > Utilities > Verify Data.

• If the Verify Utility returns the message "QuickBooks detected no problems", your file is ready to be backed up.
• If the Verify Utility returns a message "A data problem prevents QuickBooks from continuing", continue with performing Solution 

We also have online videos and other resources that can guide you to use products easily. Browse through these links to access them:

• Tutorials
• Community Guide

Keep me updated in the comments if you have further concerns about condensing your company file. I'm just a reply away. Keep safe and have a good one.

Thank you for your reply!  In the QBWin, after Verify Data fails, I find this:

verify.c (16253) : CHECKPOINT: 65280: Thu Feb 1 10:58:34 Verify Rebuild: VerifyStuckPaychecks took 6.627100 milliseconds. ErrorFound:0
verify.c (16253) : CHECKPOINT: 65280: Thu Feb 1 10:58:34 Verify Rebuild: PaymentExtensions took 0.588600 milliseconds. ErrorFound:0
attributecontainer.cpp (3606) : MESSAGE: 65280: Thu Feb 1 10:58:34 LVL_ERROR--Error: Unable to read company file attributes - owner id = {8DFA6C49-14E4-48C9-BD8B ...} .

verify.c (16253) : CHECKPOINT: 65280: Thu Feb 1 10:58:34 Verify Rebuild: AttributeContainers took 37.305000 milliseconds. ErrorFound:1

It doesn't seem to be associated with a specific product.  Or should i be looking for something else?  Thank you!