Help Desk

Computing & Information Services

Securely Removing Temporary Files on a Mac

Web browsers and email programs cache (keep copies of) each page you visit. Every modern web browser has a tool for erasing your cache, and sometime browsing history as well, but you may wish to invest in a third-party tool which can erase all of your programs’ caches in one operation.

Below, we provide individual instructions for removing temporary files from Safari, Firefox, and Thunderbird.  For erasing all the temporary files at once, we recommend NetShred X.  

Note: Remnants of other cached files for applications like Microsoft Word may still linger on your computer.  Securely erasing free space may help, but if you need a more secure solution, talk to CUS.

Reset Safari 

  1. From the Safari menu, select Reset Safari…
  2. A dialog box appears telling you what Safari will erase. Click the Erase button.

Clear Private Data in Firefox

  1. From the Tools menu, select Clear Private Data…
  2. A dialog box appears telling you what Firefox will erase. You may check any or all of the boxes. Click the Clear Private Data Now button. 
  3. To make sure the data is unrecoverable, follow the instructions on securely erasing data.

Use NetShred X

  1. Get a copy of NetShred X from Mireth Software ($19.95).
  2. Quit all web browsers and email clients and run the software.
  3. Since NetShredX can overwrite data a number of times, you won’t need to follow the steps for securely erasing data.

Thunderbird Email Headers

None of the above methods will prevent someone on your machine from seeing the headers (usually subject line, sender, and date) in Thunderbird, even if you don’t have your password stored. They will not be able to read the files easily, and if you’ve used NetShredX they won’t be able to read them at all, but they will be able to see the headers. 

To prevent this from happening, you could use Webmail.  Or remove all traces of Thunderbird and then securely erase your trash.  

Contact CUS with any questions about removing temporary files on your Mac. 

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