CCleaner doesn’t clean every account by default. If necessary, reinstall CCleaner and choose the option to make it accessible to all users when it appears. Alternatively, install it for individual user accounts as and when needed. If you choose the latter option, you’ll need to log into each user account in turn before running CCleaner.There are several things that can prevent the portable version of CCleaner (www.snipca.com/16391) from working. First, make sure you’re launching the correct file for your version of Windows, because the portable edition comes in 32bit and 64bit versions. Trying to launch CCleaner64.exe on a 32bit machine will result in an error message. If you see a Security Warning message, click Run. If the User Account Control (UAC) dialogue box then appears, click Yes. Finally, you need to be logged in as an administrator for all CCleaner’s features to work.If CCleaner slows to a crawl, you may have intentionally (or inadvertently) enabled secure-file deletion. To cheek, click Options followed by Settings and then look in the Secure Deletion section. Select ‘Normal file detection’ for the fastest speed, or ‘Secure file detection’ and ‘Simple Overwrite (1 pass)’ for safer deletion that’s still pretty nippy.Ifyou’ve installed the excellent free CCleaner plug in CCEnhancer (www.snipca.com/16390) and are wondering why its extra definitions haven’t appeared in CCleaner itself, it’s because CCEnhancer doesn’t actually come with any definitions you have to download them separately. Launch CCEnhancer then click the blue Download Latest button, and then launch (or restart) CCleaner.There’s a hidden option in CCleaner that preserves recent temporary files. This is enabled by default, so to ensure everything is deleted, click Options, Advanced, then clear the tick from the ‘Only delete flies in Windows Temp folders older than 24 hours’ box. There’s a similar option below it for the Recycle Bin, if you’re having the same problem with that.CCleaner has to access the internet to download updates, and so does CCEnhancer. This may occasionally trigger warning messages from your firewall. Once you’ve read the warning, click the relevant button (Allow, Yes or Continue) to let the program proceed. This typically occurs only once, but if it happens repeatedly look in your firewall for an option to activate exceptions for CCleaner and CCEnhancer.The most likely cause is changes made to the Windows Registry. Before cleaning the Registry, CCleaner offers to make a backup: you should always click Yes, so you can return to your previous state if things go wrong. By default, these backups are stored in your My Documents folder, so use Windows Explorer or File Explorer to navigate there then double click the most recent backup – it’ll have a REG (.reg) file extension. When the Registry Editor dialogue box appears, click Yes to confirm the restore. If Windows won’t even launch then, restart in Safe Mode (tap F8 after your computer powers up then use the arrow keys and Enter to choose Safe Mode) then follow these instructions.