Manual Rescan and Full Rescan Interval

If I set Rescan Interval to 23 hours and 12 hours later I manually press the Rescan button, does the next automatic rescan occur 23 hours after the last AUTOMATIC rescan or 23 hours after the MANUAL rescan?

What I’m really trying to do is to make my rescans occur in the early morning before I login. I’m running Syncthing on an Apollo Lake machine (underpowered) and the machine is very slow during a rescan. So I set a 20 hour rescan interval and I set Windows to wake at 6 AM. After a few days, that ought to cause my machine to wake at 6 AM and run a rescan before I login at 7 AM. I think…

The point of my rescan timing question is that I configured this setup mid-day, and I’m thinking I can goose it to make it happen sooner by manually running a rescan at 7 AM tomorrow.

Automatic rescans run after last scan (manual or automatic), but they do not happen at exactly the configured interval. It mainly depends on how long the last scan took. So if you set it to 1 day and the rescan takes 1 hour, the next automatic rescan is shifted by that time.

Syncthing always does a rescan when it is started so that no changes are missed. That should be good for you.

You can try running Syncthing as service:

If you want a rescan at a specific time, you can use a batch file with a single line that does the manual rescan for you. see

Thanks. I’m not starting Syncthing at 7 because I’m just waking the PC, not logging in to it.

So it sounds like the rescan interval is the number of seconds since the last rescan (of any type) completes. My rescans complete in well under an hour, and I (almost) always get 8 hours of sleep, so I’ll set my rescan interval to 20 hours and I’ll hit Rescan first thing tomorrow.

Or I could schedule the 6 AM wake-up event to run a batch file to run a POST. Fortunately, they recently added curl to Windows.


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I am fairly certain a manual scan does nothing to the rescan timer.

There’s also a randomness of about ± 15% on the time, iirc.

Also, by default, waking after sleep makes syncthing restart, which would perform the scan.

Well shucks. I’m going to have to learn about restartOnWakeup. Full scan on restart is just intolerable on an Apollo Lake machine. (Mine really does have to sleep when not in use, for a variety of reasons.)

Have you tried setting Max Folder Concurrency = 1 in menu “advanced settings” - “options”? This works wonders for my small linux server with spinning disks :rocket:

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What @uok said, plus a full folder scan shouldn’t be cpu intensive, that points at the storage (filesystem and/or where/what the storage is).

I think my file system access is more CPU intensive than for some Syncthing users, because my file system is encrypted.

What kind of encryption are you using? As long as it is hardware accelerated, there should barely be any noticeable overhead. It it is not hardware accelerated, then yes, accessing the files will likely cause higher CPU usage.

I personally have everything encrypted with BitLocker in Windows with basically no impact on the system resources.

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