Delete Your Mac's Cache to Resolve Difficult-to-Diagnose Problems

2008-07-03

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Read This First!

I wrote this article a while ago on an older Mac OS X computer. It worked great for me, and as you can see from the comments below, it’s worked great for others too. However, a handful of users experience problems. I’m not sure if it’s due to a glitch in the Mac software, if this really only worked well on specific Mac OS versions, or if there’s something on a users computer that causes the cache deletion to fail for another reason (like software or hardware). Whatever the case, back up your Mac’s data and settings first, and delete cache after you’ve tried every other option for resolving your problem.

How to Delete Cache

If you own a house, you’ve probably had it sprayed for termites. If you have a dog, it probably wears a flea collar. If you have a car, you regularly have the oil changed. If you do what your doctor tells you, you go in once a year for a checkup. You do these things to prevent problems, catch problems early, and deal with problems as (or before) they arise, hopefully finding small problems and fixing them before they become even bigger ones. You need to take that same kind of care with your computer. In this article, you’ll learn how to delete the Library cache to avoid future problems, or to fix a corrupt cache.

A cache is where OS X stores data it needs to access often (such as extensions and icons). Storing data in cache makes your Mac run faster because it can obtain the data it needs quickly. Sometimes the cache gets corrupt, though, because of software updates, conflicts, and unexpected quits, and this can cause problems. You should delete the library cache occasionally to maintain your Mac’s performance.

You might experience application or system crashes or see seemingly random problems that don’t seem to be caused by anything in particular at all. This could be caused by a corrupt library cache. To prevent the cache from becoming corrupt, you should delete everything in the Caches folders once a month, about the same time you run the file system checker mentioned in a previous article.

Occasionally, cleaning the cache causes problems. This is extremely rare, but possible. For instance, you may be prompted to approve applications you’ve already cleared and approved, and under Tiger, fonts you’ve disabled may become enabled. If you have passwords “remembered” in the cache these may be lost. We haven’t been able to uncover any other problems that can occur, but to be safe, make sure your data is backed up before starting.

Here’s how to clean your caches:

1. Choose Users>your user name>Library>Caches.

2. From the Menu bar, choose Edit>Select All.

3. Drag all of the items to the Trash.

4. From the Macintosh HD, choose Library>Caches.

5. Choose Edit>Select All, and drag the items to the Trash. You’ll be required to type in an administrator’s password.

6. Restart your Mac.