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Unable to run log file backup on "Public Folder Database". Please disable circular logging or run database backup instead

Published: 5 June 2018Updated: 26 October 2026
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Error

Unable to run log file backup on "Public Folder Database". Please disable circular logging or run database backup instead.

Error message: unable to run log file backup on Public Folder Database

Cause

Circular logging is turned on for the database. With circular logging, Exchange overwrites old transaction log files, so there is no complete set of logs for a log file (incremental) backup. Turn circular logging off so the BOBcloud software can back up and manage the transaction logs, or run a full database backup instead.

In Exchange 2013 and later, public folders are stored in public folder mailboxes, so change the setting on the mailbox database that holds them. In Exchange 2010 and earlier, change it on the public folder database.

Fix

Exchange 2016, 2019 and Subscription Edition: Exchange Admin Center

  1. In the Exchange Admin Center (EAC), go to Servers → Databases.
  2. Select the database and click Edit.
  3. Click Maintenance, clear the Enable circular logging tick box, and click Save.
  4. Dismount and mount the database, or restart the Microsoft Exchange Information Store service, for the change to take effect.

Exchange Management Shell

Set-MailboxDatabase -Identity "<database name>" -CircularLoggingEnabled $false

Then dismount and mount the database, or restart the Microsoft Exchange Information Store service.

Older versions of Exchange have the same Enable circular logging setting in the database (or storage group) properties.