It may not be Opus itself but a component something else has installed which gets involved with searching. If file contents are being searched then the problem may also be antivirus scanning the files, which can block processes from doing anything else until the scan completes.
Which search are you using? The Windows Search field at the top-right of the lister? Or the Tools > Find Files panel?
What are your search criteria?
Which types of files are in the folders you're searching?
Assuming you're using Opus 12, send us some snapshots made while the search is happening and won't cancel quickly. We can use them to see what's going on, and whether the delay is inside Opus or something else.
If you're on Opus 12, your account still says Opus 9, which may mean it's linked to the wrong licence. We can unlink the account if you want to link it to a different licence.
(Linking updates versions automatically if you upgrade an existing licence, but if you buy two completely separate licences for different versions then the system won't know you have one if you're linked to the other.)