FreeFileSync Forum

Take a look at my earlier posts on 'FFS performance and 'disablelastaccess' setting in Windows 10' and see if it applies to your issue.

Take a look at my earlier posts on 'FFS performance and 'disablelastaccess' setting in Windows 10' and see if it applies to your issue.

Have been working for 3 weeks with last access timestamping disabled, without any issues. I guess it might matter in a setting where access to files is monitored for security or forensic reasons. For me changing the setting rescued FFS on Windows 10, restoring the rapid scans and instant USB drive ...

I had a similar issue, described in my posts on October 15, 16, 21.
If you are on Windows, the 'disablelastaccess" setting has a big effect on file comparison speed.
Check its value with
fsutil behavior query disablelastaccess
If the value is 2, try changing it to 1:
fsutil behavior set ...

To clarify the comments on this on 16 October:

Windows 10, by default, records the date/time of every access to a file in each file timestamps field.
If FFS has to scan 10s of thousands of files for a sync operation, there is a significant overhead to recording the access times, which appears to be ...

Both PCs (Lenovo Thinkpad X1 Carbon, W10 Pro, October 2019; and Dell Optiplex W10 Pro, April 2019) arrived with last access timestamping enabled (NtfsDisableLastAccessUpdate disabled). Microsoft's name for this setting is very confusing. If "DisableLastAccess" is set to "Disabled", it means that ...

see my earlier posts on 06 Mar 2019 and 01 Apr 2019

I routinely sync between work and home PCs via a flash drive. To do that I invoke FFS 3 separate times to sync 3 different folders, each containing about 40000 files. FFS does the first one rapidly, no problem. But the 2nd and 3rd time FFS slows ...

see my post on March 6

Problem turned out to be the Everything app running in the background. Everything was probably interfering with access by FFS to the Shadow Copy system. Issue solved by setting Everything prefs for clean exit without running in the background.

No, further testing shows *extremely* slow folder traverse on repeated invocation of FFS, with USB drive set for 'Quick Removal' in Device Manager.

OK, now testing disabling write caching on the USB drive. That may have done the trick, second invocation worked fine.

Using FFS v10.9 under Windows 10 / 1809
Syncing between laptop and USB flash drive

Traversing the folders and saving files works without issue on the first invocation of FFS.

The problem occurs if I close FFS and then invoke it a second time to sync another set of files under different folders ...