Instant crash at startup (fatal python error) #68143

New Issue

Robert · 2019-08-02T19:03:02+02:00

Robert commented

2019-08-02 19:03:02 +02:00

System Information
Operating system: Windows 10
Graphics card: Nvidia GeForce RTX 2070

Blender Version
Broken: 2.80
Worked: 2.79

Newly installed Blender 2.80 crashes instantly at startup. There were no such issues with a previously installed Blender 2.79 version.
Running it from the command line shows that there is a python error (see attached logfile). log.txt

Exact steps for others to reproduce the error

Install Blender 2.80
Try to run blender.exe

**System Information** Operating system: Windows 10 Graphics card: Nvidia GeForce RTX 2070 **Blender Version** Broken: 2.80 Worked: 2.79 Newly installed Blender 2.80 crashes instantly at startup. There were no such issues with a previously installed Blender 2.79 version. Running it from the command line shows that there is a python error (see attached logfile). [log.txt](https://archive.blender.org/developer/F7646080/log.txt) **Exact steps for others to reproduce the error** 1. Install Blender 2.80 2. Try to run blender.exe

Robert commented

2019-08-02 19:03:02 +02:00

Added subscriber: @Robert-Lasch

Ray molenkamp commented

2019-08-02 19:06:07 +02:00

Added subscriber: @LazyDodo

Ray molenkamp commented

2019-08-02 19:06:07 +02:00

does it work when you start blender using the blender_debug_log.cmd batch file located in your blender folder?

does it work when you start blender using the `blender_debug_log.cmd` batch file located in your blender folder?

Robert commented

2019-08-02 19:09:04 +02:00

It does not work and produces a log file with the same error.
blender_debug_output.txt

It does not work and produces a log file with the same error. [blender_debug_output.txt](https://archive.blender.org/developer/F7646088/blender_debug_output.txt)

Ray molenkamp commented

2019-08-02 19:14:31 +02:00

was this the .msi installer or the .zip?

Robert commented

2019-08-02 19:19:42 +02:00

It was the .msi installer.
It might also be relevant that I have other python distributions installed on the system besides the one bundled with Blender. Could those be interfering with the bundled version?

It was the .msi installer. It might also be relevant that I have other python distributions installed on the system besides the one bundled with Blender. Could those be interfering with the bundled version?

Ray molenkamp commented

2019-08-02 19:25:43 +02:00

It could be, but the batch file i made you run temporary reset the PYTHONPATH environment variable that it generally uses to find 'the wrong python' so yeah i'm kinda stumped here,

My running theory was the unzip bailed out prematurely but given you didn't use the .zip that's out the window as well.

It could be, but the batch file i made you run temporary reset the PYTHONPATH environment variable that it generally uses to find 'the wrong python' so yeah i'm kinda stumped here, My running theory was the unzip bailed out prematurely but given you didn't use the .zip that's out the window as well.

Robert Guetzkow commented

2019-08-02 19:58:43 +02:00

Added subscriber: @rjg

Robert Guetzkow commented

2019-08-02 19:58:43 +02:00

Looks like an encoding/decoding problem. 0xfc is indeed not valid in UTF-8. Do you happen to have an ü somewhere in a path or file that may be read by Blender? I suspect there is some error where wide characters aren't properly converted to multibyte.

Looks like an encoding/decoding problem. `0xfc` is indeed not valid in UTF-8. Do you happen to have an `ü` somewhere in a path or file that may be read by Blender? I suspect there is some error where wide characters aren't properly converted to multibyte.

Robert commented

2019-08-02 21:06:49 +02:00

I just checked using Process Monitor (https://docs.microsoft.com/en-us/sysinternals/downloads/procmon).
It does not look like Blender is opening any files besides ones from the python/lib directory in the blender installation path. Those shouldn't have any encoding issues, as they were just freshly installed.
The installation path itself also does not contain any umlauts.
Is there anything else I could do to figure out which file is causing the issue?

I just checked using Process Monitor (https://docs.microsoft.com/en-us/sysinternals/downloads/procmon). It does not look like Blender is opening any files besides ones from the python/lib directory in the blender installation path. Those shouldn't have any encoding issues, as they were just freshly installed. The installation path itself also does not contain any umlauts. Is there anything else I could do to figure out which file is causing the issue?

Robert commented

2019-08-02 22:38:56 +02:00

Changed status from 'Open' to: 'Resolved'

Robert closed this issue

2019-08-02 22:38:56 +02:00

Robert self-assigned this 2019-08-02 22:38:56 +02:00

Robert commented

2019-08-02 22:38:56 +02:00

Just figured it out. There was a .pth file in a site-packages folder of one of the other python distributions on the system. That file pointed to a path containing an ü.
Apparently this was never a problem for the already installed python distribution, but the one bundled with Blender was sensitive to it.
Removing the offending path in the .pth file resolved the problem.
Thank you everyone.

Just figured it out. There was a .pth file in a site-packages folder of one of the other python distributions on the system. That file pointed to a path containing an `ü`. Apparently this was never a problem for the already installed python distribution, but the one bundled with Blender was sensitive to it. Removing the offending path in the .pth file resolved the problem. Thank you everyone.

Robert Guetzkow commented

2019-08-02 23:24:04 +02:00

Added subscriber: @ideasman42

Robert Guetzkow commented

2019-08-02 23:24:04 +02:00

@Robert-Lasch Thank you for investigating this!

@LazyDodo @ideasman42 Is there something about the encoding of .pth files that Blender currently doesn't consider, but can and should? I guess the problem is that the file encoding is assumed to be UTF-8 without trying to identify the actual file encoding?

@Robert-Lasch Thank you for investigating this! @LazyDodo @ideasman42 Is there something about the encoding of .pth files that Blender currently doesn't consider, but can and should? I guess the problem is that the file encoding is assumed to be UTF-8 without trying to identify the actual file encoding?

Ray molenkamp commented

2019-08-02 23:30:49 +02:00

Ideally python would not be looking at anything outside it's own folder, and should leave other pythons on the system alone, If someone can talk me into re-creating the conditions that @Robert-Lasch was having did i'd be happy to take a stab at this

Campbell Barton commented

2019-08-03 02:38:48 +02:00

We try not to interfere with Python defaults so Python developers get an environment which works like a regular installation, however we need to set the standard encoding since Blenders data-block names are utf-8.

Checking site-packages site.py where the error is raised & Python is using open() without any encoding arguments when loading the .pth files.

This might be a bug in Python, since it could set the encoding:

  f = open(fullname, "r", encoding=sys.getfilesystemencoding())

At the very least it could warn but not prevent Python from starting entirely.

Note, this error can be redone in Linux easily.

mkdir -p ~/.local/lib/python3.7/site-packages
python -c 'import sys, random; random.seed(1); sys.stdout.buffer.write(bytes([random.randint(0, 255) for i in range(2000)]))' > ~/.local/lib/python3.7/site-packages/paths.pth

Now Python & Blender fail to start.

We try not to interfere with Python defaults so Python developers get an environment which works like a regular installation, however we need to set the standard encoding since Blenders data-block names are `utf-8`. Checking site-packages `site.py` where the error is raised & Python is using `open()` without any encoding arguments when loading the `.pth` files. This might be a bug in Python, since it could set the encoding: ``` f = open(fullname, "r", encoding=sys.getfilesystemencoding()) ``` At the very least it could warn but not prevent Python from starting entirely. ---- Note, this error can be redone in Linux easily. ``` mkdir -p ~/.local/lib/python3.7/site-packages python -c 'import sys, random; random.seed(1); sys.stdout.buffer.write(bytes([random.randint(0, 255) for i in range(2000)]))' > ~/.local/lib/python3.7/site-packages/paths.pth ``` Now Python & Blender fail to start.

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Instant crash at startup (fatal python error) #68143