Peculiar "Unused File Extension" entries in Registry analysis.

[A_Pickle]

So, I was fixing a computer belonging to the father of a friend of mine. I have a pretty set routine when fixing computers, and I proceeded as usual. Install Windows, install drivers, install applications, install updates, restore backup data, run CCleaner and then Defraggler.

 

CCleaner's "Cleaner" portion is working just fine -- however, the "Registry" portion is giving me a few "Unused File Extension" entries that just... don't jive with what I've done. For one, it's listing .iso, .cue, and .img as several of them, when in fact I know that each of these is associated with InfraRecorder (a disc burning program).

 

It's odd. I've had file extension problems caused by CCleaner in the past, but it was long ago.

[kroozer]

Do yourself a favor. Untick ☐Unused File Extensions.

[GoneToPlaid]

So, I was fixing a computer belonging to the father of a friend of mine. I have a pretty set routine when fixing computers, and I proceeded as usual. Install Windows, install drivers, install applications, install updates, restore backup data, run CCleaner and then Defraggler.

 

CCleaner's "Cleaner" portion is working just fine -- however, the "Registry" portion is giving me a few "Unused File Extension" entries that just... don't jive with what I've done. For one, it's listing .iso, .cue, and .img as several of them, when in fact I know that each of these is associated with InfraRecorder (a disc burning program).

 

It's odd. I've had file extension problems caused by CCleaner in the past, but it was long ago.

 

Was InfraRecorder installed on the computer and was it told to associate those file extensions with InfraRecorder? If not, then whenever the OS encounters files with the ISO, CUE AND IMG extensions, Windows will merrily create default registry entries for those file extensions but not associate those extensions with any particular program. Basically, the OS is simply keeping track of whatever unknown file types it encounters. Regardless, any Unknown File Extensions which CCleaner finds in the registry can be safely deleted or ignored -- your choice, and absolutely no harm done either way. Or as krooser mentions, you can simply deselect Unused File Extensions.

[Nergal]

please read the advice in my signature especially in regards to unused extensions

[RunAmok]

Nergal and Kroozer are absolutely right. And GoneToPlaid just hasn't been bit yet. It is NOT always safe to simply delete everything CCleaner thinks is unused. A couple years ago the first run of a new release told me that there were a bunch of "unknown" file extensions. I'd always seen a few - like .dbx from Outlook Express which appeared to be correctly associated in the file type list - and just let it delete them, but this time the list was a lot longer and it deleted several critical extensions like .msi. I had to restore from the backup to get Windows back to normal working condition and even then it still gives me that same long list in the newest version. I learned the lesson of checking closely before deleting anything I'm not sure about. I've left the "Unused File Extensions' unchecked ever since because it still gives me the same long list if I try it.