Error Solved: Outlook PST Error 'Attempting to Validate BBT Refcounts'

Bharat BhushanSolution Manager
Experts in data recovery from corrupt Exchange mailboxes, SQL database, and Outlook emails.
While repairing a PST file with ScanPST.exe, many users have encountered the error "Attempting to Validate BBT Refcounts". In this article, we are going to describe the reasons and solution to fix the error.

MS Outlook is the most used email client and stores its contents in PST file format. Sometimes, when the PST file gets corrupt and the user tries to repair it using Scanpst.exe, then it may happen that the PST file becomes completely inaccessible and displays the following error message: “Attempting to Validate BBT Refcounts”.

Many Outlook users are proactive and maintain a backup of their email client through an added PST file to import the content from backup PST, in case the PST file gets corrupt. For those who are unaware of the backup feature, they still have an option to resolve the issue by creating a new PST and copying data from old PST file. If the data is still not recoverable, a corrupt PST file can be repaired with a reliable professional software solution.

Working on any error is easier when the user understands the cause of the problem. The user receives the Outlook PST error in the Log Report which shows the following:

  • “Attempting to validate BBT Refcounts.”
  • “Couldn’t find BBT entry in the RBT (211C8)”

The following factors lead to the error:

  1. Outlook is unable to locate the BBT entry of PST file
  2. PST file size is more than defined limits: In Outlook 2002 and earlier versions, the PST file size was limited to 2GB. If the file size exceeded the 2GB limit, Outlook exhibited strange behavior and the PST became corrupt
  3. Severely corrupted PST file
  4. Corruption due to Add-ins

Resolve the issue by removing its possible cause

The following methods can resolve the Outlook PST Error: Attempting to Validate BBT Refcounts:

  1. Remove the possible causes which were responsible for this error
  2. Remove the PST corruption issue with disable add-in option
  3. Reinstall MS Outlook to resolve BBT errors
  4. Create a new PST file
  5. Use professional applications to repair Outlook PST file

The Solutions in detail:

      1. Remove the possible causes

Reduce the size of PST by deleting unimportant messages from Inbox, Sent Items, Drafts, Conversation History and other folders and then emptying the Deleted Item folder. Reducing the PST size as Outlook defined limits may resolve the error.


Reducing the file size may not fix the corruption in PST file, hence the error is not resolved.

        2. Disable Add-ins

Sometimes, corrupt add-ins can also lead to PST file corruption. In that case, the best solution is to disable Outlook Addis.


To disable Outlook Add-ins, Go to Tools > Trust Center > Add-Ins disable the Mindjet/MindManager add-in and other Add-Ins.


Add-ins may not have corrupted the PST file.

       3. Create a New PST file and Run Scanpst.exe

Create a new PST file and repair the newly created PST:
Go to File>Account Settings>Account Settings>Data Files tab>click Add button.

Once you create a new data file, move or copy content from old PST file to new PST file then run inbox repair tool or Scanpst.exe on new PST file to verify the result


ScanPST.exe repairs the PST file for minor issues only and cannot deal with severe corruption in PST file hence, may not resolve the error

Performance is not optimal for large size PST file. The exe file shows slowness issue and in extreme cases, may lead to termination of the repair process

       4. Reinstall MS Outlook

Locate the MS Outlook email client in the Control Panel. Uninstall the current email client

Reinstall MS Outlook email client


The PST file of uninstalled-Outlook remains corrupt even after reinstalling the email client which creates a hindrance in importing old PST data and hence the earlier Outlook data is still inaccessible.

        5. Repair PST with Stellar Phoenix Outlook PST Repair Software - Technician

This software resolves corruptions in a PST file. This software repairs emails from encrypted and password-protected PST files and provides the option of selective recovery in multiple file formats. Also fixes large size PST which is the primary cause of the error: Attempting to Validate BBT Refcounts, by Split and compact option.


Follow the below process to Repair PST File:

  • Install and open the software
  • Select the PST file for repair and click on Repair button. Alternately, click on the Find button to locate the PST file if the location is not known
  • The software displays a preview of repaired Outlook components for verification
  • Click on the Save button and select the right option to save the PST file
  • Save the corrected file at the preferred location as new PST file.


Outlook PST error statistics are not alarming but the user's incapability to resolve the error is a cause for concern. Creating a new PST and copying data from old to new PST is a good option. Still, there is a genuine worry as the users may not get the results desired; and when it comes to unprecedented productivity, users should opt for Software fixes. Why?

The reason is that the limitations posed by the manual method are overcome with software fixes. This professional software provides maximum recovery within the least possible time. Like, in this case, the Outlook PST error attempting to validate BB Refcounts is resolved with Stellar Phoenix Outlook PST Repair software - Technician.

Bharat BhushanSolution Manager
Experts in data recovery from corrupt Exchange mailboxes, SQL database, and Outlook emails.

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