If CCleaner is not already running, open Start Menu by clicking on Start button or pressing Windows Key on keyboard.
Window XP users should choose All Programs, find CCleaner folder and click CCleaner:
Windows Vista and 7 users should type "ccleaner" into Search box and click CCleaner in search results.
In Windows 8 and 8.1 Start screen, type "ccleaner" (you do not need to open Search charm) and click it in the results. Touch-screen owners can just scroll to the end of Start screen and tap CCleaner.
You can disable User Account Control prompts in Advanced Options of CCleaner. Open Options tab on the left and click Advanced. Then enable the Skip User Account Control warning option.
Multiple user accounts considerations
Please be aware that free version of CCleaner affects only global temporary files (created by Windows itself) and those of currently logged-on user. If you have multiple user accounts on your PC and you need to gain maximum disk and registry optimization, you must either run CCleaner from each account separately or use the Run as different user command. The latter is available in Windows 7 and newer: hold down Shift key and right-click CCleaner icon to access it. You must then enter the other user's name and password.
You can also buy CCleaner Professional to do the job for multiple accounts automatically.
Which items to select in CCleaner
CCleaner has several sections by program types. You can right-click any section to use commands like Check all, Uncheck all, Analyze, Clean or Restore default state. For individual items, Analyze, Clean and Restore default state commands are available.
So if you want to, you can clean or analyze any single item or section available, or restore CCleaner default selections.
Now that CCleaner is open, deselect Internet Explorer History, Recently Typed URLs, Index.dat files, Last Download Location and Autocomplete Form History. Click to select Saved Passwords. It is extremely important to clear browser cache from stored passwords, because any malware can steal the login details easily. Use Password Safe for safely storing and filling login information instead.
Please note that selecting Saved Passwords triggers a warning dialog. Click OK.
Under Windows Explorer, deselect all items. These are things you probably do not want to be removed, as they help you find previously used web addresses, commands and user names. Select these items only if you want to completely remove traces of your computer usage - for example, to clear Windows Search history (not Internet Explorer!), activate the Search Autocomplete option.
In Windows Vista, 7, 8 and 8.1, you can select Thumbnail Cache if you recently deleted hundreds of photos or videos, otherwise Windows will just rebuild the same previews of the same photos and videos you already have on your computer.
For Windows 7, 8 and 8.1, you can select Taskbar Jump Lists if you want to completely remove history for applications' Jump Lists.
If your computer is not connected to a local network (LAN) that uses Workgroups or Domain, select Network Passwords. These are stored user names and passwords that connect to remote printers and file shares. Without any file and printer sharing, there is no need to keep those credentials.
In System section, select all items except for Font Cache. These are temporary files generally not needed, plus items on Desktop and Start menu that are invalid (pointing to files or programs that do not exist anymore).
You should select the Font Cache option only after you've removed many fonts - the cache will be rebuilt anyway.
If you experience frequent Windows crashes (aka Blue Screens of Death) and restarts, do not select Memory Dumps here! Use free WhoCrashed for analysing the crash dump files and determining the cause of problems. After you've resolved the problems, you can safely delete the old dumps.
Below are Windows XP and Windows Vista/7/8/8.1 versions of CCleaner:
For Windows XP, scroll down and select Old Prefetch data, Environment Path, IIS Log Files and Hotfix Uninstallers in Advanced section. The last item will probably free up loads of disk space if you've used Windows XP on the PC for years.
For Windows Vista, 7, 8 and 8.1, select Old Prefetch data, Environment Path and IIS Log Files. The IIS option might not be listed in Windows 8 and 8.1.
Never enable the Windows Event Logs option! Event Viewer helps a lot in troubleshooting, plus user and system monitoring.
You should also check what's under Applications tab. If you have other Internet browsers (Mozilla Firefox, Apple Safari, Opera, etc) installed, uncheck their Internet History, Session and Saved Form Information boxes first.
Select Saved Passwords for all browsers (this will open the same warning dialog as with Internet Explorer, click OK there) and then select Compact Databases item for Firefox, Google Chrome and Opera.
Please note that you should close Internet browsers before moving on to the next step!
For other types of applications, it is usually safe to select all items.
You could click the Analyze button next and see an analysis about what's going to be deleted, but that is usually a waste of time - you're going to delete unnecessary files anyway. Move right on by clicking the Run Cleaner button.
CCleaner will warn you that you are going to delete files. Click OK.
Although CCleaner is able to remove items related to Internet Explorer while the browser is open, it will display a warning if you have some other Internet browser open. Close the browser first and then click OK.
After a few seconds to a few minutes or so, you'll see a "CLEANING COMPLETE" message with a summary of files deleted.
Since version 4.0, CCleaner has an option to detect and remove duplicate files. This is a powerful tool, so please use it with extreme care!
The feature can be accessed by clicking Tools tab and then opening File Finder.
By default, all options are selected in the Match by and Ignore sections, and you should not change these unless you really know what you're doing.
In the Include tab, hard drives are selected by default. You can also search other drives if you need to, but in most cases just click Search.
The search for duplicates might take several minutes, depending on hard drive speeds and the amount of data to compare. After it has finished, a "File search has completed" message appears. Click OK.
Go through the list and see which files are safe to delete.
Do not select any files you have no idea about! Always leave duplicates in Program Files, Program Files (x86) and ProgramData folders unselected - these files are most probably required by Windows and/or installed programs.
You can choose the files to remove using check boxes. Additionally, you can right-click on an item, expand Select duplicates in and click a folder to quickly mark all detected duplicates in it. But please do not use the root of drive (for example, C:\) here - deleting all these duplicates will most probably ruin your Windows installation and your day!
In the example below, nVidia installer cache folder is used, but you should probably leave it alone if you have one. This is just a screenshot.
You could also use the Select All of Type item on the right-click menu to quickly select all duplicate JPG image files, for example.
Then you can also mark certain folders as excluded - this will prevent displaying duplicates there now and in the future. For example, if you have linked some folders with Junction or MKLink to get around the limitations of SkyDrive, Dropbox or Google Drive, you must exclude the symbolic links to prevent deleting important files. In the example below, the SkyDrive folder contains such links, and if I erased any files in it, the originals would also be deleted.
If you have not intentionally set up symbolic links, you do not need to worry about these.
To exclude a folder, right-click on an item in it, expand Exclude and choose the path.
You can later manage exclusions easily in the Exclude tab of CCleaner File Finder.
Now comes the final warning - File Finder removes the selected files permanently, without moving them to Recycle Bin! You might also want to download and install Recuva before erasing anything. Basic instructions for using the undelete/file and folder recovery program are available in this article.
Please double-check (and triple-check) the list of selected items and only then click the Delete selected button on the bottom right.
File removal probably takes just a few moments. After completion, a "The selected files have been successfully deleted" dialog appears. Click OK.