Environment Path - This Cleaning Rule will clear the “PATH” User Variable in your system environment variables back to its default.

Window Size/Location Cache - When you open and close Windows Explorer, Windows records folder settings for window position, sort order, columns, folder type, toolbar toggles, and search result views.

Tray Notifications Cache - This cache stores information about any items that have ever appeared in your System Tray and whether or not you have set them to Hide, Hide When Inactive, or Always Show.

Menu Order Cache - When you drag and drop items on the Start menu into different locations, Windows stores this information in the Menu Order Cache.

The cleaner can delete the prefetch data, clearing up space if there are many cached programs that no longer exist or haven't been used for a long time.

Old Prefetch Data - To run quickly, Windows uses prefetch files to store information about programs that you frequently use.

Windows Event Logs - This will clear the entries in your Windows Event Viewer, which can often be used to diagnose problems occurring with your computer but can typically be deleted if the computer is working properly.

Files and data in your Windows operating system (advanced): None of these Cleaning rules are enabled by default, and we recommend only enabling them for specific troubleshooting purposes. We recommend only using these options for troubleshooting: You can see some in the screenshot below as checkboxes you can select beneath the Windows tab, including the highlighted Advanced section. These are the specific files and data that you allow CCleaner to delete from your system. What is Custom Clean?Ĭustom Clean is a function within CCleaner that allows you to customize how the app cleans different parts of your PC, such as your operating system and applications (like web browsers).

If you want to find out more about your operating system's specific cleaning rules in CCleaner, skip to Files and data in your Windows operating system (advanced) below.

We explain how you can clean your Windows operating system using CCleaner's Custom Clean.

Old prefetch data