Symptoms 

In the remote of local backup log, you see error messages similar to:

• ERROR: 0x30000: Failed to insert folder cache entry: database is locked [5] [5 (0x5)] {eFS:Cliesqlite:452}

Known Causes and Resolutions 

The software uses an embedded sqlite database to assist in keeping track of which files have changed since the last backup. The sqlite embedded database can return this error message when other applications or the operating system is interfering with reading or writing to this file. This includes:

• Old software: For local disk backups on software versions older than 3.7.8 there is a rare race condition that can cause this error to happen. Use the software updater to update to version 3.7.8 or later to make sure this is not causing the problem.
• Anti-virus and anti-malware scanners: The sqlite engine can open and close the embedded database file several times per second under certain workloads. In cases like this, a slow antivirus engine can interfere. To eliminate this cause, edit the policy of any antivirus or antimalware scanners as follows:
• Exclude the program files directory that contains the backup program files, including subdirectories. (e.g., C:\Program Files\Online Backup)
• For local backups, exclude the local backup destination. For example, if you are backing up the data to G:\MyBackups, edit the antivirus policy to exclude G:\MyBackups from the scan.
• File system fragmentation: Accounts that are backing up tens of millions of files can experience this issue if the filesystem that contains the sqlite embedded database is extremely fragmented. Check the fragmentation level of the filesystem that contains the backup program (and for local backups, also check the filesystem containing the backed up data), and defragment the filesystem if needed.