Can’t activate Trim View in Adobe Illustrator

Also make sure you did not hide artboards.

https://illustrator.uservoice.com/forums/333657-illustrator-desktop-feature-requests/suggestions/39157192-trim-view-stops-working-when-artboards-are-hidden

Once you let us know if this happens to all documents or just this one, that will eliminate most of the possibilities.

In this case was a modified print.ai that was too large 300mb.  https://community.adobe.com/t5/illustrator-discussions/why-is-trim-view-greyed-out/td-p/13358096

I see you have inkquest and am wondering if that might be conflicting.

Until we get more information to be able to help you. try Shift F to go into prevention mode, and escape to exit. That key command works if you are not setting type.

What OS version are you running? Has it worked before?