Crash error

Out of the blue, dopus crashed on me and won't restart, even after a reboot. It says 'The error (0xC0000005) occured in thread 'dopus_main' at address 0x4420B7'

Any ideas?

It would help if you gave some details like the version of Opus you're using, what operating system you're using, what you were doing when it crashed, and so on.

If it were me however I'd go direct to the support page at:

gpsoft.com.au/Support.html

And request official support for this problem.
Note you will need to supply your registration code unless you're an evaluation user.

There could be a file in the directory Opus is showing when it starts which causes a plugin or shell extension to crash:

[Crash, exit or high CPU when viewing certain directories)