I was troubleshooting a friends PC because they had somehow lost the majority of their fonts. I looked in Control panel under Fonts, and only 10 remained out of about 145 previously. However, I could still see the fonts in the when using the CMD window using the ATTRIB command, so the physical files were still there.
I restored the ccleaner .reg backup file, and the fonts returned to normal after a reboot. It appears that some link to the fonts were broken by the regclean process. Though I cannot reproduce this issue on my machine, I thought it was worth reporting it. Oh, and I am sorry that I didn't think to keep the .reg file. I wish I had it to attach.
It happened on Windows 7 Home Premium 64. Hope this helps, somehow.
You need to follow safer protocols when using any registry cleaner.
I appreciate your advice about following safer protocols, but I did not run the cleaner. I fixed the issues caused by it.
If a registry cleaner is finding an entry it incorrectly thinks is orphaned and decideds to take it out; it's a bug. At the least an exlcusion needs to be written. While cleaning the registry in small bits is ideal in finding out which key is causing an error when removed, it makes no overall difference in safety to go in small bits, or to follow the recommendation of ccleaner to clean the keys with a single click.
Actually it does, imho, make a difference, because if you had looked at the list you would have immediately noticed that it was listing every font and you would have only removed only (in other words "sparingly") items you knew you didn't need.
The registry scan helps identify items which you may not want; it is nowhere near 100% correct ever, and yet it is (arguably) the most gentle registry "cleaner" out there. Tons of users come here having their entire PC unable to start because of over-zealous cleaning (read that as "wholesale cleaning every suggestion without even looking"), thus my advice which I got so sick of typing I put it in my signature. Honestly you got off easy, being it was only your fonts.
I've never quite grasped the reason for the font section, so I leave it alone. For years I ignored the .net registry entries that always come up in missing .dll after every .net version update (1 to 1.1 to 2 to 3 to 4) until I followed my advice and removed them (and only them) in a bundle and called the reg file net.reg. luckily, they caused no issue and I didn't need to keep the reg file. Had I not followed my advice and I lost access to a separate program from a registry entry unrelated to .net i'd either have to keep my backup .reg file for ever (or until no item removed had bugged me which without knowing what's in the file is the same as forever) or restore every not broken entry just to restore one good one.
Not about safety as much as piece of mind and easier fixing.
As a final point, restoring the .reg file (as you found) does not always fix all the issues. If you had only removed what you knew you didn't need, you would not have to try my next solution for the fonts that did not get fixed
You might want to tell your friend if they continue to use the registry cleaner to untick 'Fonts' in the registry cleaner section, as that's likely what caused it.