# Dependency files opened with write access

**URL:** <https://forum.aousd.org/t/dependency-files-opened-with-write-access/2472>\
**Category:** USD\
**Created:** [May 23, 2025, 10:57am UTC](https://forum.aousd.org/t/dependency-files-opened-with-write-access/2472 "2025-05-23T10:57:11Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![diegogarces](https://avatars.discourse-cdn.com/v4/letter/d/bb73d2/32.png) [@diegogarces](https://forum.aousd.org/u/diegogarces)\
**Post date:** [May 23, 2025, 10:57am UTC](https://forum.aousd.org/t/dependency-files-opened-with-write-access/2472/1 "2025-05-23T10:57:11Z")

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Hello everyone!  
We are having some crashes when rendering the a shot in multiple machines at the same time. We wanted to rule out problems with having too many files opened at the same time. The server should handle any number of files open for reading at the same time, but not for writing.  
Is it possible that USD opens reference files (usdc or vdbs) for writing under some circumstances?

Thanks a lot!

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**Author:** ![dhruvgovil](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.aousd.org/dhruvgovil/32/3_2.png) [@dhruvgovil](https://forum.aousd.org/u/dhruvgovil)\
**Post date:** [May 23, 2025, 2:19pm UTC](https://forum.aousd.org/t/dependency-files-opened-with-write-access/2472/2 "2025-05-23T14:19:44Z")

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I don’t believe USD ever opens a write file handle to the same location as its reading from.

Does your server handle memory mapping files?

You could also monitor the file handles your process has open though and see if any of them are opened for write.

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**Author:** ![spiff](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.aousd.org/spiff/32/22_2.png) [@spiff](https://forum.aousd.org/u/spiff)\
**Post date:** [May 25, 2025, 1:35am UTC](https://forum.aousd.org/t/dependency-files-opened-with-write-access/2472/3 "2025-05-25T01:35:16Z")

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I don’t think that’s quite true - in the Save() pathway for pre-existing crate files, [we do reopen the asset for in-place updating](https://github.com/PixarAnimationStudios/OpenUSD/blob/53d7d647d293fe1aaeb03d2186e8cdeefe09a6fd/pxr/usd/sdf/crateFile.cpp#L2484-L2488), but that would happen **only** if the application made changes, and then explicitly called Stage or Layer Save(), which seems unlikely (though possible) for a rendering app.