VST3 Plugins

Cannot load any of the Steinberg dynamics plugins (compressers, limiter,de-esser etc). They appear greyed out in the insert slots. Other plugins present and correct. The missing ones used to work, I’ve not done any reconfiguring that would account for the problem.
Any help much appreciated, thank you.
Cubase 5.5.3, Windows XP 32 bit.

Things I would try…
New project.
Trash preferences.
Reinstall. (last resort)

“Constrain delay compensation” enabled…!?

“Constrain delay compensation” enabled…!?[/quote]

That’s it! Excellent work, hole in one!
Thank you very much indeed.
Is that a recognized bug?

Constrain delay compensation" enabled…!?

No, it works as expected.