Questions about HKEY_CLASSES_ROOT

mathieu

Hello,

I have a question about the registry part HKEY_CLASSES_ROOT:

I read on wikipedia (http://en.wikipedia.org/wiki/Windows_registry) that performance problems and instability can especially begin when a program registers itself as a class in HKEY_CLASSES_ROOT. I discovered that lots of traces of some programs I removed ages ago are still to be found in that part of my registry. But what kind of keys are safe to remove, and what kind are not? (I'm speaking about traces that can be found with the PT 2006 Registry Finder and that are not found by the Registry Cleaner).

For example, I found:

HKCR\CLSID\{1EDA6FE8-4F13-4BFD-865B-411C13AEA41A}\LocalServer32\, @, C:\Program Files\Picasa2\PicasaMediaDetector.exe /StiDevice:%1 /StiEvent:%2, 11.12.2005, 21

Is it safe to remove this? (Picasa was removed a long time ago...)

For some applications I removed in the past, the amount of entries that can still be found is just crazy. For example "Copernic Agent":

HKCR\CLSID\{563C2ADC-0363-4141-9E0D-49ED544E3B82}\ProgID\, @, CopernicAgent.Application, 15.12.2003, 18

HKCR\CLSID\{6F480F82-C3A6-4D35-96F7-B297AD49FBE8}\InprocServer32\, @, C:\Program Files\Copernic Agent\CopernicAgentExt.dll, 15.12.2003, 18

HKCR\CLSID\{6F480F82-C3A6-4D35-96F7-B297AD49FBE8}\LocalServer32\, @, C:\Program Files\Copernic Agent\CopernicAgentExt.dll, 15.12.2003, 18

HKCR\CLSID\{CBBD301C-32AA-4D15-A9BA-3611386AB945}\ProgID\, @, CopernicAgentExt.ApplicationHelper, 15.12.2003, 18

HKCR\CLSID\{CE3E9421-ED45-46D2-AC22-83480922C17D}\ProgID\, @, CopernicAgentExt.TAddInSearch, 15.12.2003, 18

HKCR\CLSID\{E2D73AF3-BC7B-48A3-BD4C-633957462149}\, @, Copernic Search Application Object, 15.12.2003, 18

HKCR\CLSID\{E2D73AF3-BC7B-48A3-BD4C-633957462149}\ProgID\, @, CopernicSearch.Application, 15.12.2003, 18

HKCR\CLSID\{F2E259E8-0FC8-438C-A6E0-342DD80FA53E}\, @, Copernic Agent, 15.12.2003, 18

HKCR\CopernicAgent.Application\, {KEY}, {KEY}, 15.12.2003, 18

HKCR\CopernicAgent.Application\, @, N/A, 15.12.2003, 18

HKCR\CopernicAgent.Application\Clsid\, {KEY}, {KEY}, 15.12.2003, 18

HKCR\CopernicAgent.Application\Clsid\, @, {563C2ADC-0363-4141-9E0D-49ED544E3B82}, 15.12.2003, 18

HKCR\CopernicAgentExt.ApplicationHelper\, {KEY}, {KEY}, 15.12.2003, 18

HKCR\CopernicAgentExt.ApplicationHelper\, @, ApplicationHelper Object, 15.12.2003, 18

HKCR\CopernicAgentExt.ApplicationHelper\Clsid\, {KEY}, {KEY}, 15.12.2003, 18

HKCR\CopernicAgentExt.ApplicationHelper\Clsid\, @, {CBBD301C-32AA-4D15-A9BA-3611386AB945}, 15.12.2003, 18

HKCR\CopernicAgentExt.TAddInSearch\, {KEY}, {KEY}, 15.12.2003, 18

HKCR\CopernicAgentExt.TAddInSearch\, @, N/A, 15.12.2003, 18

HKCR\CopernicAgentExt.TAddInSearch\Clsid\, {KEY}, {KEY}, 15.12.2003, 18

HKCR\CopernicAgentExt.TAddInSearch\Clsid\, @, {CE3E9421-ED45-46D2-AC22-83480922C17D}, 15.12.2003, 18

HKCR\copernicagentsearch\, {KEY}, {KEY}, 15.12.2003, 18

HKCR\copernicagentsearch\, @, Copernic Agent Protocol Extension, 15.12.2003, 18

HKCR\copernicagentsearch\, URL Protocol, N/A, 15.12.2003, 18

HKCR\copernicagentsearch\shell\, {KEY}, {KEY}, 18.01.2007, 13

HKCR\CopernicSearch.Application\, {KEY}, {KEY}, 15.12.2003, 18

HKCR\CopernicSearch.Application\, @, Copernic Search Application Object, 15.12.2003, 18

HKCR\CopernicSearch.Application\Clsid\, {KEY}, {KEY}, 15.12.2003, 18

HKCR\CopernicSearch.Application\Clsid\, @, {E2D73AF3-BC7B-48A3-BD4C-633957462149}, 15.12.2003, 18

HKCR\PROTOCOLS\Handler\copernicagent\, {KEY}, {KEY}, 15.12.2003, 18

HKCR\PROTOCOLS\Handler\copernicagent\, CLSID, {A979B6BD-E40B-4A07-ABDD-A62C64A4EBF6}, 15.12.2003, 18

HKCR\PROTOCOLS\Handler\copernicagentcache\, {KEY}, {KEY}, 15.12.2003, 18

HKCR\PROTOCOLS\Handler\copernicagentcache\, CLSID, {AAC34CFD-274D-4A9D-B0DC-C74C05A67E1D}, 15.12.2003, 18

HKCR\TypeLib\{06C5B3FE-EAA7-4E90-AB90-85A2E7761AF2}\1.0\, @, Copernic Search Library, 15.12.2003, 18

HKCR\TypeLib\{06C5B3FE-EAA7-4E90-AB90-85A2E7761AF2}\1.0\0\win32\, @, C:\Program Files\Copernic Agent\CopernicAgentExt.dll, 15.12.2003, 18

HKCR\TypeLib\{06C5B3FE-EAA7-4E90-AB90-85A2E7761AF2}\1.0\HELPDIR\, @, C:\Program Files\Copernic Agent\, 15.12.2003, 18

HKCR\TypeLib\{8FA46A54-F0C1-44AE-AF2B-5DA85D675171}\1.0\, @, Copernic Agent COM, 15.12.2003, 18

HKCR\TypeLib\{8FA46A54-F0C1-44AE-AF2B-5DA85D675171}\1.0\0\win32\, @, C:\Program Files\Copernic Agent\CopernicAgent.exe, 15.12.2003, 18

HKCR\TypeLib\{8FA46A54-F0C1-44AE-AF2B-5DA85D675171}\1.0\HELPDIR\, @, C:\Program Files\Copernic Agent\, 15.12.2003, 18

All these entries are to be found in the HKEY_CLASSES_ROOT, which means that they may have great impact on the performance of my system, as explained in wikipedia.

Are there clear rules I can follow to discover which keys are safe to remove and which are not?

redseujac

I think al those "Picasa" and "Copernic" entries can be removed without harm for your PC and anyway you could always restore them if necessary with the backup tool :

I don't think there's a general rule to know what's safe to remove or not. Trial and error method?

mathieu

Hello Redseujac,

thank you very much for your answer.

I agree I could just try and restore if necessary. But I understood that modifying the HKEY_CLASSES_ROOT part of registry can end up in a disaster... not being able to start Windows again and having to reinstall... I really don't fancy that!

That's why I'd like to know if somebody could point areas that are less dangerous in HKEY_CLASSES_ROOT, and also if there are parts of HKEY_CLASSES_ROOT that can be pointed as extremely dangerous areas.

Or does anybody know a website that gives the kind of information I'm looking for? I haven't been able to find any. Most site only give general information about the registry.

blackdex

Hello Mathieu,

HKCR can be tricky sometimes.

But if it only containts software you know isn't installed anymore, then you can safely remove them.

Mostly HKCR is full of references to file-types different programs support.

And extra items that appear in the context-menu when you right-click on things like .mp3 files etc..

If you remove items which are still used by some kind of software, you can destroy the link between them.

Like, if you remove .mp3 items, you probebly can't dubble-click on those files to start them anymore.

Anyway, like Redseujac told, those entries look safe to remove, if you haven't installed Picasa and/or Copernic.

mathieu

Thank you very much, BlackDex and redseujac!

I gave it a try, and everything went well.

I will keep you posted if I discover interesting things to tell about this.

Thank you once again!

Bye.