CCleaner 4.03.4151 (64-bit) running on (64-bit) Windows 7 Professional SP1
The Registry tool recently began reporting two filename extensions as "unused" which it has not previously reported. I believe it began reporting them in version 4.02 and now in 4.03:
.key
.xpi
Both are used in C:\Program Files (x86)\Users\Stardance\AppData\Roaming\Mozilla Firefox\.....\Profiles\1234567.default\extensions
.xpi is a known Firefox extension.
.key is commonly used for two or three different purposes, including storing the license key for installed software.
Have fun! ;-)
[ Admin: I hope you have good eyes to read this tiny font that your forum software uses! I don't, so don't blame me if the content is as blurry as the text since it is, after all, your DEFAULT (pun intended). ]
so are you saying that when you run the reg cleaner it is listing those file name extensions as unused but you can in fact see that you have them in a folder somewhere ?
(PS: Ctrl + and Ctrl - is pretty standard on all browsers to zoom in & out respectively. comes in handy for those who are poorly sighted )
So far as I am aware the location of the XPI etc. is not relevant.
If I create a file ABCD.EFG then Windows will see this as having the extension EFG
and then Windows wants to know how to execute it and registry cleaner reports it as an unused extension.
PDF was an "unused extension" because I used a Portable PDF reader and my habit was to launch the reader and the reader then opened any PDF file that I drag-dropped onto it.
More recently I altered the readers settings to register so that double clicking any PDF file would open the reader and accept the file.
( By doing this I degraded portability for the sake of convenience.)
I suspect that the Registry Cleaner is correctly stating that Windows does not know how to open your XPI file if you double click it.
Firefox is on a mad rabid release cycle which is breaking addons,
and it is possible that you see this is a new problem due to changes in Firefox and not changes in CCleaner.
XPI isn't registered by Firefox to my knowledge as a file you can double-click and work with. However; If you register it with firefox.exe you can then just double-click it and Firefox will launch to install the add-on and it will no longer be detected as invalid.
Or you could register it with your Zip/UnZip tool such as; 7-Zip, WinRAR, WinZip, etc., since XPI is a renamed ZIP extension.
Edit:
[ Admin: I hope you have good eyes to read this tiny font that your forum software uses! I don't, so don't blame me if the content is as blurry as the text since it is, after all, your DEFAULT (pun intended). ]
I have the same problem which is why I tweak the text size to display bigger in my web browser(s).