I just experienced the same. I've used Boxcryptor for years with little issue. Yesterday, it stopped working. When I go to start the program, I can see it start in Task Manager (the Boxcryptor process kicks off). After a few seconds, it changes to "Boxcryptor (Suspended)", then exits out.
I tried to generate a debug log according to the instructions, but did not get the log file to show up on my desktop. I did reinstall the latest version this morning, it didn't help.