I'm using the latest version of Boxcryptor Classic (1.6.405.102), and it is crashing often.
After a few weeks, I noticed that it's crashing whenever McAfee VirusScan Enterprise 8.7 does a weekly full scan. I can restart Boxcryptor fine without any problems, so it's not a matter important files getting incorrectly quarantined or deleted.
This didn't happen with the previous version of Boxcryptor Classic, everything including McAfee configured identically.