TortoiseSVN database locking errors after disabling Samsung RAPID mode

One of my users is getting database lock errors from TortoiseSVN after disabling Samsung RAPID mode. What's a good way to find out what programs had a file locked recently?

Since it requires a reboot to tu off/on and there's no apparent speed benefit to RAPID mode, I shouldn't tu it back on to test. He's a high-end user, so I'm trying to waste as little of his time as possible. The error started the same day we disabled RAPID mode, and doesn't happen every time he commits.

sqlite[S5]: database is locked, executing statement 'PRAGMA case_sensitive_like=1;PRAGMA synchoouse=OFF;PRAGMA recursive_triggers=ON;PRAGMA foreign_keys=OFF;PRAGMA locking_mode = NORMAL;PRAGMA joual_mode = TRUNCATE;' Another process is blocking the working copy database, or the underlying filesystem does not support file locking; if the working copy if on a network filesystem, make sure file locking has been enabled on the file server.

Details : Windows 10, TortoiseSVN 1.9.3, and a variety of development tools which don't coect to SVN directly.

I tried this on StackOverflow yesterday.