I was copying large files over to my computer for video editing and keeping an eye on available hard drive space I knew I should have had just enough space to put everything. However, as I was getting close to filling up my hard drive, the available free space suddenly jumped by about 30GB. Any idea what happened?

  • Do you use NTFS compression? – davidbaumann May 9 '18 at 12:48

This can happen with Transactional NTFS. The free space is used for storing the transaction, once the transaction is committed the free space can be reclaimed.


The OS automatically emptied your trash, deleted TMP files, etc....

Happens on Windows and OS X.

What is your OS?

  • Windows 7. I emptied my trash earlier already and actually had to uninstall a few programs and clean up the computer a little before i transfered files to my computer. I didn't do anything with the temp files but can temp files really add up to 30GB? – Faken Jun 8 '10 at 2:55
  • The other thing that can happen is a delayed recognition by the OS of additional space... – drewk Jun 8 '10 at 3:06

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