Can't edit selection in Audition

[Ali5D62]

I've always been able to edit the Waveform file in Audition - simply deleting selections within the file.

For some reason, it's now not allowing me to do this - can anybody explain what could be the cause of this?

Screenshot attached

[SteveG_AudioMasters_]

You will lose any specific user-settings you've made, but the most obvious thing to try is to reset Audition's Preferences system. That's really easy to do - just restart Audition with the Shift key held down. If that makes no difference, then try uninstalling and reinstalling the software using Adobe's CCcleaner.

CCcleaner app