Unable to execute the tool. Class not registered - Issue re-occurs.

[ownersrep]

The error "Unable to execute the tool. Class not registered." continually appears when I choose an item on the design palette. The Home -> Build Tab buttons are all questions marks as well. 

Per previous support recommendations, I reinstall the product.  But the issue is temporarily resolved, only to reappear the next day. I am reinstalling the product daily.

Any thoughts on a permanent fix?

- New Install, v2013

[pendean]

Try this test: If you close and restart ACA2013 now (not overnight), does it also fail?

If not, with a working session of ACA2013 and at the end of a work day (before you go home) close and restart it to ensure it's still working, then unplug your PC from your network and internet. Come back the next morning, plug back in and start ACA2013. Is it dead as you've noticed previously, or working?

[ownersrep]

After reinstall yesterday, it worked with several different files at different times without a problem.

Tried today and the error is back. 

I am unable to unplug from the network and power down as this machine is needed for other services.

[pendean]

Without a detailed test to identify the culprit, there is no magic bullet. Consult your I.T. about addressing these "unable" issues and have them help you figure out what happens overnight to your system.

Something is getting replaced. Your issue is not ACA all on it's own. Good luck, post back if you all find something but cannot explain it.

[ownersrep]

It appears I have identified the culprit as being Iolo System Mechanic.  After each reinstall, the program keeps "fixing" registry entries causing the program to break. Not sure what the program doesn't like about Autocad but once I suspended the program, Autocad works fine.

[David_W_Koch · Accepted solution]

Registry cleaners have a tendency to do that to AutoCAD.  If you registry cleaner program allows it, exclude the registry setting of AutoCAD Architecture from the scrutiny of the registry cleaner.

[Anonymous]

I recently installed AutoCAD Architecture 2014 and I am getting the same message, "Unable to Execute the tool. CLass not registered"  I tried Repair and this had no impact on the problem,  Any help would be appreciated, thank you

[Anonymous]

am unable to find the registry values as stated  as i am using civil 3d 2012 on windows 7 64 bit

please let me know as i dont want to take the reinstallation. The repair work is also giving error. if there is some sort of entry through registry it will be quite easy