# What's the difference between .zraw file and .raw file

**URL:** <https://discourse.slicer.org/t/whats-the-difference-between-zraw-file-and-raw-file/34971>\
**Category:** Support\
**Created:** [March 19, 2024, 9:55am UTC](https://discourse.slicer.org/t/whats-the-difference-between-zraw-file-and-raw-file/34971 "2024-03-19T09:55:52Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Chuan](https://avatars.discourse-cdn.com/v4/letter/c/4da419/32.png) [@Chuan](https://discourse.slicer.org/u/Chuan)\
**Post date:** [March 19, 2024, 9:55am UTC](https://discourse.slicer.org/t/whats-the-difference-between-zraw-file-and-raw-file/34971/1 "2024-03-19T09:55:52Z")

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Hi all,

Recently I meet a very strange problem when I save my data as mhd file.  
Sometimes it will save as a group of mhd file + raw file, which looks normal and correct. But sometimes it will save as a group of mhd file +zraw file, with a temporary file named TempWrite…

I tried with several version of 3D slicer (4.10.1 4.11 5.0.3), all of them have this kind of problem.  
I wonder if it is normal, and what’s the difference between zraw file and raw file?

Best,  
Chuan

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**Author:** ![muratmaga](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/muratmaga/32/3622_2.png) [@muratmaga](https://discourse.slicer.org/u/muratmaga)\
**Post date:** [March 19, 2024, 3:33pm UTC](https://discourse.slicer.org/t/whats-the-difference-between-zraw-file-and-raw-file/34971/2 "2024-03-19T15:33:47Z")

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I don’t use mhd and not very familiar, but I imagine zraw means compressed raw. So if you are having trouble, just uncheck compress option when you are saving the file.