If you watch scanning process you can usually see what plug-in the scanner is getting hung up on. Once you find it - either fix it's problem, delete it, or move it out of your scanned folders.
If you can't identify the offender.
Check to see if you have the "Re-scan Existing Plug-ins" or "Re-scan Failed Plug-ins" checked and uncheck them - under Edit/Preferences then File/VST Settings.
If you have both these options checked the scanner will continuously crash at the same spot (when it hits the same plug-in) and never get beyond it.
Once you uncheck them - the scanner will still crash the next time you run it, but the following time it should skip the offending plug-in and continue where it left off.
Hope this helps.