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My CCleaner Premium Duplicate Finder displays multiple .dll files. What to do?

BARRY G. VARGUS Sr 0 Reputation points
2025-04-20T20:54:41.7466667+00:00

I ran my CCleaner Premium app today. The Duplicate Finder displays tons of duplicate files. I usually know how to handle them regarding deleting some and which ones. Today I ran into something I'm unfamiliar with. It displayed approximately 30 .dll files that were either duplicates or triplicates. I Googled what's a .dll file? AI answered and said that when deleting duplicate .dll files, first download Process Explorer and test each one to see if they're being used. However, when I went to the learn.microsoft.com > Sysinternals > to Download Process Explorer I did some more research and it doesn't appear I can either find out that way, maybe it won't show a certain .dll is in use but will be in the future and how do I know, or maybe AI was wrong and it just wont give that info I'm looking for. I'm a novice however, I do learn fast but it just doesn't look as though it would work. Does anyone with knowledge of .dll's or Process Explorer have an answer as to what I should do with Duplicate .dll's because I hear they are very important?

Sysinternals
Sysinternals
Advanced system utilities to manage, troubleshoot, and diagnose Windows and Linux systems and applications.
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  1. RLWA32 48,151 Reputation points
    2025-04-21T07:02:35.27+00:00

    @BARRY G. VARGAS Sr, It is not unusual for more than one copy of a dynamic link library (DLL) to be present on a system. Although many DLLs used by applications are located in a system folder (e.g., C:\Windows\System32) where they can be shared some applications are designed to work with particular versions of DLLs. Consequently, when such applications are installed they also come with their own private copies of the DLLs that they need to function.

    Your concern about the AI "solution" is well founded. It is not practical to run every application on your system and use Process Explorer to identify every DLL that the running application uses or may use during program execution. And even if you could do such a thing, are you sufficiently well informed to understand the results?

    If your system is running properly and is not suffering from a critical shortage of disk space it seems to me that recovering disk space by deleting DLLs poses a significant risk compared to a minimal benefit. Deleting an application's private copy of a DLL could cause that application to fail and become unusable. If disk space is a critical problem there are likely other methods to recover space that would be more effective and pose less risk.

    Based on what you have said in your question I recommend that you do nothing with respect to the multiple copies of the DLLs.

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