Antivirus and endpoint protection software can significantly reduce the performance of file backup and synchronization operations. In some cases, a profile that should complete in minutes can take hours. This is because antivirus software intercepts every file operation that SyncBack performs, adding overhead to each read, write, rename, and delete.
How Antivirus Software Interferes
Real-Time File Scanning
Most antivirus products include a real-time protection feature that intercepts file operations at the operating system level. Every time SyncBack opens a file to read its contents, the antivirus software also reads and scans the file before allowing SyncBack to proceed. When SyncBack writes a file to the destination, the antivirus scans the newly written file as well.
This means that for every file copied, the antivirus effectively doubles (or more) the number of file read operations. For a profile that copies thousands of files, this overhead adds up quickly.
Behavioral Analysis
Modern antivirus products monitor application behavior in addition to scanning individual files. A backup application that rapidly opens, reads, and closes thousands of files in succession can trigger behavioral analysis heuristics. This can cause the antivirus to throttle SyncBack or spend additional time analyzing each operation before allowing it to continue.
Controlled Folder Access (Windows Security)
Windows 10 and later include a feature called Controlled Folder Access, which is part of the ransomware protection in Windows Security. When enabled, it blocks unauthorized applications from modifying files in protected folders such as Documents, Pictures, and Desktop.
If SyncBack has not been added to the list of allowed applications, Controlled Folder Access will silently block write operations to protected folders. SyncBack will detect these failures and retry or report errors, but the repeated failed attempts and error handling add significant overhead. This can also cause files to be skipped or the profile to fail entirely.
Archive and Compressed File Scanning
Some antivirus products are configured to scan inside compressed files such as Zip archives. If SyncBack is creating or updating a Zip backup, the antivirus may attempt to decompress and scan the archive contents each time the file is modified. This can be extremely slow for large archives.
Symptoms
The following symptoms may indicate antivirus interference:
- Profiles that previously ran quickly now take much longer, especially after installing or updating antivirus software.
- High CPU usage from the antivirus process during a profile run.
- File copy speeds that are far below what the storage and network should support.
- Intermittent "access denied" or "file in use" errors during copying.
- Files being quarantined or deleted by the antivirus immediately after SyncBack copies them to the destination.
- The SyncBack process being flagged or blocked by the antivirus.
Recommendations
Add SyncBack to the Antivirus Exclusion List
Most antivirus products allow you to exclude specific applications or folders from real-time scanning. Adding the SyncBack executable to the exclusion list prevents the antivirus from scanning files as SyncBack accesses them. This is the single most effective step you can take.
You should add the following to your antivirus exclusion list:
- The SyncBack executable file (e.g. SyncBackPro.exe, SyncBackSE.exe, or SyncBackFree.exe)
- The SyncBack installation folder
- If possible, the source and destination folders used by your profiles
Note that excluding folders from antivirus scanning means files in those folders will not be scanned in real time. They will still be scanned during scheduled antivirus scans. Consider whether this trade-off is acceptable for your environment.
Allow SyncBack Through Controlled Folder Access
If you are using Windows Security with Controlled Folder Access enabled, you must add SyncBack to the list of allowed applications:
1. Open Windows Security.
2. Go to Virus & threat protection.
3. Under Ransomware protection, select Manage ransomware protection.
4. Under Controlled folder access, select Allow an app through Controlled folder access.
5. Add the SyncBack executable.
Disable Archive Scanning for Backup Destinations
If your antivirus scans inside compressed files, consider excluding your backup destination folder from archive scanning. This prevents the antivirus from repeatedly decompressing and scanning your Zip backup archives.
Schedule Backups to Avoid Antivirus Scan Times
If your antivirus runs scheduled full scans at specific times, avoid scheduling SyncBack profiles during those periods. Running both simultaneously will cause heavy disk I/O contention and slow both operations considerably.