CCleaner 2.11.636 still won't remove an apparently errant registry key in Vista Home Premium. When I run a registry scan, CClenaer reports the following error: Under the Problem column -- Missing TypeLib Reference; Under the Data column -- IOutlook Plug - {4A345IBE-99E0-476C-AE7F-C2A5671AC22E}; Under the Registry Key column -- HKCR\Interface\A9CC9305-0A30-4015-92A0-071EE24E720}. If I right-click on the line and then click on Open in RegEdit, the registry opens. When I try to delete the key, an error box pops up with the following message: Cannot delete {A9CC9305-A030-4015-92A0-071EE24E720}: Error while deleting key.

Anyone have any ideas about how to correct this so that the same problem doesn't keep coming up every time I run CCleaner?

Hi rdy, and welcome to the forum.

I don't have Vista, and I don't use Outlook, but I'll hazard a guess and say it sounds like a residue from a previously installed plugin, or maybe a plugin that hasn't been removed properly.

I take it there's no evidence of the plugin in Add/Remove programs, so if I'm anywhere close maybe you can delete it in Safe Mode. If remnants of the plugin are still on your pc, maybe some part of Windows is hanging onto that key.

Just a bit of guesswork here, but Safe Mode might be worth a try.

Running CCleaner in Safe Mode did the trick and the key has finally been deleted from my registry. Thanks for your help!