XnView: MP 1.10.1 - 64 bit
OS: Windows - 64bit
It looks like the application cannot handle UNC paths longer than 255 characters
Effect: When you try to open files whose path is an UNC path and it's longer than 255 characters, XnView shows an Error dialog with "File not found!" written inside. Shorter file paths are handled just fine.
The difference between a shorter than 255 characters path and a longer than 255 charaters file paths is in the beginning of the path.
The longer one will start with \\?\UNC\server.domain.whatever while the shorter one starts with \\server.domain.whatever
To reproduce:
1. Try to open an image file whose file path is UNC and longer than 255 characters
Actual behaviour (bug): The application cannot find the file
Expected behaviour: The application open the chosen file
1.10.1 Cannot open UNC paths if longer than 255 characters
Moderators: xnview, Dreamer
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ugo92
- Posts: 2
- Joined: Mon Mar 02, 2026 9:13 am
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jkm
- Posts: 402
- Joined: Sat May 11, 2024 12:43 am
Re: 1.10.1 Cannot open UNC paths if longer than 255 characters
Welcome to the forums...
Please read up on MAX_PATH, a historical limitation in Windows.
https://learn.microsoft.com/en-us/windo ... s=registry
To exceed it, you must explicitly enable LongPaths on your machine, individual applications must opt-in to it, and still not all Windows functions support it.
Have you enabled LongPaths?
Hopefully this sheds some light on what's going on.
Please read up on MAX_PATH, a historical limitation in Windows.
https://learn.microsoft.com/en-us/windo ... s=registry
To exceed it, you must explicitly enable LongPaths on your machine, individual applications must opt-in to it, and still not all Windows functions support it.
Have you enabled LongPaths?
Hopefully this sheds some light on what's going on.
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xnview
- Author of XnView
- Posts: 47521
- Joined: Mon Oct 13, 2003 7:31 am
- Location: France
Re: 1.10.1 Cannot open UNC paths if longer than 255 characters
you enter in the pathname filed, a path like \\?\UNC\server.domain.whatever, right?
Pierre.
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ugo92
- Posts: 2
- Joined: Mon Mar 02, 2026 9:13 am
Re: 1.10.1 Cannot open UNC paths if longer than 255 characters
Thanks for your answers!
If i go "deep enough" in the levels the file path becomes longer than 255 characters and the image doesn't open.
I checked its path with right click -> copy as path, that's where I noticed the differences in the beginning of the path
Yes, LongPaths is enabledHave you enabled LongPaths?
No, i use windows file explorer to reach \\server.domain.whatever\level1\level2\...\levelN\ then i double click image.jpg to open it in XnViewMP.you enter in the pathname filed, a path like \\?\UNC\server.domain.whatever, right?
If i go "deep enough" in the levels the file path becomes longer than 255 characters and the image doesn't open.
I checked its path with right click -> copy as path, that's where I noticed the differences in the beginning of the path
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xnview
- Author of XnView
- Posts: 47521
- Joined: Mon Oct 13, 2003 7:31 am
- Location: France
Re: 1.10.1 Cannot open UNC paths if longer than 255 characters
i've sent you a test versionugo92 wrote: Wed Mar 04, 2026 8:38 am No, i use windows file explorer to reach \\server.domain.whatever\level1\level2\...\levelN\ then i double click image.jpg to open it in XnViewMP.
If i go "deep enough" in the levels the file path becomes longer than 255 characters and the image doesn't open.
I checked its path with right click -> copy as path, that's where I noticed the differences in the beginning of the path
Pierre.