Leap Day 2016 Crash
Due to a bug in leap year calculations, attempting to use Beyond Compare 4's cloud profiles (Amazon S3, Microsoft OneDrive, and WebDAV/web folders) on February 29th 2016 will not work and will cause a crash. Changing your system date to March 1st will allow the OneDrive and WebDAV support to work. Unfortunately Amazon S3's authentication relies on the current system date and will not work unless it's accurate.
The issue will resolve itself on March 1st and we'll have a permanent fix in the 4.1.4 release.
We sincerely apologize for the inconvenience.