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GeoDjango - FileNotFoundError: Could not find module 'C:\OSGeo4W\bin\gdal304.dll' (or one of its dependencies)

I am trying to install GeoDjango what turns out to be much harder than I thought. After I installed the OSGeo4W on my 64 Bit Windows 10 system I set everything up in the settings.py file but now I get this error:
FileNotFoundError: Could not find module 'C:\OSGeo4W\bin\gdal304.dll' (or one of its dependencies). Try using the full path with constructor syntax.
I also set the GDAL_LIBRARY_PATH but it just won't work.
GDAL_LIBRARY_PATH = "C:\\OSGeo4W\\bin\\gdal304.dll"
This is my C:\OSGeo4W\bin path and as you can see the gdal304.dll file is there
My Python is on version 3.10.6
Django is on version 4.1
I already tried to solve it by myself for a week but slowly I have no idea left on what to do

I ran into this problem too, since I updated my old GEO Django Setup today.
You may use a Docker Image as suggested by the others, but I prefere a native solution, since I don't want to spin up Docker every time I start coding.
Your solution is in the brackets: (or one of its dependencies)
You may look up the transitive dependendencies from gdal304.dll. There are several tools for this (see here). I'm using here now the Git integrated MinGW - Shell that has ldd installed. This should be the case for any (newer) Git installation on Windows.
As you can see, some dependencies are already fullfilled from your operating system. Others that are missing, have to be fullfilled from OSGeo4W. If you compare this with your bin directory from OSGeo4W you will see the Problem:
Sadly a simple "renaming" does not the trick. I was lucky and had not yet deleted my old OSGeo4W version. In the old files I then found the necessary DLL.
So, long story short: You need the jpeg.dll file.
There are sites like "windll.com" or "dll-files.com", but I would not recommend using them. I don't trust these sites. You may install something like "MSYS2", "Cygwin" or even "MVSC", install the "libjpeg-turbo" library and then finally copy & paste the necessary DLL file.
This is also suggested on the official Site for libjpeg-turbo: https://libjpeg-turbo.org/Documentation/OfficialBinaries
But this seems like a lot of work for someone who just want to have the DLL file, but then again: Never download a library blindly from the Internet and load it into your application. These libraries could do anthing!

Why is python27.dll not part of python installed folder but in Windows system folder

As described in: http://bugs.python.org/issue22139, the python27.dll is installed in the windows systems (in my case C:\Windows\Systems32) folder.
But I would like to know why? Why is it not installed next to the python.exe, for example in C:\Python27\?
Reason I ask: I've made a mercurial hook in python that our developers need to use to check if the commit message is valid. It checks a.o. for a valid JIRA issue number. To prevent all our developers to install python themselves and install the required modules manually (a lot of work and errorprone), I zipped the python installation and asked the developers to unzip it locally. But they can't run it, because the python27.dll is missing, or worse, they already have another minor version of python installed, and the hook will fail due to the wrong python27.dll used. Confusing.
If I just add the python27.dll (the correct version) to the zip file, it all seems to work great. So, why is it not installed in that location in the first place? What is the advantage of installing it in C:\Windows\System32?
Hope someone can explain this to me!
Thanks in advance,
Tallandtree.

I use the Anaconda Python distribution from http://continuum.io. They put python27.dll into c:\anaconda right next to its python.exe. This distribution is also superior in that you can have multiple python environments with precisely the packages you need and switch between them easily (http://conda.pydata.org/docs/using/envs.html). You can also get the package list of one of your environments and distribute it to others.
I recommend this Python distribution over the one from python.org and Enthought, because of this issue.

.dlls are quite windows-specific files. I imagine you will have shared object (.so) files for LINUX/UNIX-specific Python stuff? You said your developer's couldn't run it, because they didn't have the correct DLL (i.e. the one relevant to their Python installation).
Also, the advantage of installing it to System32 is that it's in the default PATH. Additionally, if any other application is internally using Python and require access to the .dll file, and also NOT reference your Python directory, they will probably be looking for a location that "Actually" exists (I wanted to say guaranteed to exist, but......never mind). That location would be `C:/windows/Systems32'.

I found it to work just fine to put python27.dll in the Python directory (c:\Python27 or wherever). As long as it's in the PATH, it seems to work. I did this for a "relocatable" installation of Python. I can copy the installation directory to a Windows machine that has no Python installed, set the PATH to include that directory, and run Python, including all the libraries I had installed with pip install on the original machine.

Abnormal $PATH on OS X

I realize that this is probably a simple question but, I'm 95% my path is screwed up. The result of opening a new terminal and typing [echo $PATH] is:
/Library/Frameworks/Python.framework/Versions/2.7/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/Users/bmoog/.rvm/bin
Looking around it seems that it should be something more like:
/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/local/git/bin:/usr/X11/bin
Any guesses as to why I am going into my Python.framework?

The Python installers from python.org, and from many other sources, do not install anything into /usr/local/bin or /usr/bin. Instead, they install everything into a bin directory within the framework, and then give you an option to add that bin directory to your path. (Generally, any script that get installed either with that Python, or with packages you later install into it, also end up in the framework's bin directory.)
So, at some point, you ran a third-party Python 2.7 installer, and checked the checkbox/manually ran the post-install script/etc. to do this.
All the option does is prepend the following 4 lines to your ~/.bash_profile:
# Setting PATH for Python 2.7
# The orginal version is saved in .bash_profile.pysave
PATH="/Library/Frameworks/Python.framework/Versions/2.7/bin:${PATH}"
export PATH
(Possibly with the typo orginal for original fixed, depending on your version.)
So, you can revert by just cp ~/.bash_profile.pysave ~/.bash_profile if you're not afraid of losing any subsequent changes… or, more safely, just edit the file in your favorite text editor and remove those lines.
Of course if you do this, you will no longer be able to run that third-party Python, or its 2to3, or an ipython you installed for it, etc., without specifying a horrible absolute path…
Meanwhile, you probably didn't need a third-party Python 2.7 in the first place. Apple has been providing Python 2.7 for at least three major OS versions now (2.7.5 in Mavericks, 2.7.2 in Lion and Mountain Lion), as /usr/bin/python. If you don't want this 2.7 on your PATH, you probably don't want it at all, so I'd just uninstall it.

Check your ~/.bash_profile and then all the files it includes to see where the extra path is coming from. Somewhere there will be a line like:
export PATH=/Library/Frameworks/Python.framework/Versions/2.7/bin:${PATH}
But do you really care?

Missing 'C:\Windows\system32\python27.zip' file

I recently upgraded my Python 2.7.1 installation to 2.7.2 using the .msi installer and the process seemed to go OK. However afterwards I happened to be looking at what the default values were for sys.path and noticed the entry for 'C:\Windows\system32\python27.zip'. Wondering exactly what was in it, I decided to try opening it with a Zip utility to check out its contents — however I soon discovered that the file wasn't there (although there is a python27.dll).
Anyhow I'm now wondering if something is wrong. Several existing Python programs I frequently use all seem to work without problems, so I'm not sure whether the installation is messed up or not (or how to fix it, if it is).
Update
I'm aware of and have read PEP273, so know about .zip file modules. That's not what I'm asking about. What I want to know is the fact that there is no python27.zip installed on my system even though it's referred to in my sys.path a problem? I've never encountered problems importing standard Python libraries, which is what I would expect not having one would affect.

From PEP 273 -- Import Modules from Zip Archives:
Just as sys.path currently has default directory names, a default zip
archive name is added too. Otherwise there is no way to import all
Python library files from an archive.
...
The problem is what the name should be. The name should be linked
with the Python version, so the Python executable can correctly find
its corresponding libraries even when there are multiple Python
versions on the same machine.
We add one name to sys.path. On Unix, the directory is sys.prefix +
"/lib", and the file name is "python%s%s.zip" % (sys.version[0],
sys.version[2]). So for Python 2.2 and prefix /usr/local, the path
/usr/local/lib/python2.2/ is already on sys.path, and
/usr/local/lib/python22.zip would be added. On Windows, the file is
the full path to python22.dll, with "dll" replaced by "zip". The zip
archive name is always inserted as the second item in sys.path. The
first is the directory of the main.py (thanks Tim).

Multiple Versions of Python on my Windows machine: Which is the "right" one?

In continuing to research a solution for this question on ServerFault:
https://serverfault.com/questions/221203/mercurial-hook-fails-on-windows
I discovered an interesting and somewhat disturbing thing: I have seem three different versions of Python on my machine (four if you count the "official" version which doesn't appear to have a DLL with it....). Here's shot from my file search tool:
More Info:
I am running Windows 7 64-bit
Both the TortoiseHG and the Mercurial directories are on my path, with the Mercurial directory listed first.
I have Python 2.6 installed in c:\Python26
I have no entry for any type of PYTHON-based environmental variable. (Should I?)
I suspect that this is the source of the my problem from the question above, but I thought I'd ask here, as this is particular issue is a Python deal.
I tried to replace both DLLs with each other, but when I use the one that comes with Mercurial, then TortoiseHg stops working.
It seems to me that "there should only be one" Python on my machine. How do I achieve that?

For the problem that you mentioned earlier, the mercurial package got installed within python under mercurial home but you are executing scripts under C:\python26. So you need to install and execute your script under mercurial python
As seth mentioned earlier it is perfectly ok to multiple python homes in the same machine but you just to pay attention when installing python libraries to make sure that you are under the right home which means you set the path right before calling python.

Side note: The Python installation in "C:\Python26" installs its DLL to the Windows directory, in your case "C:\Windows\SysWOW64".
Answering your serverfault question: As you installed Mercurial as standalone version, you'll have to place any packages that are accessed by hooks into Mercurial's library folder (if it has one, could also be "library.zip").
I would recommend you to uninstall the Mercurial standalone version and instead install Mercurial with pip. This makes updates easier and you can use your normal "site-packages" directory for both normal Python libraries and hg hooks.

I would assume that tortoise/mercurial have just embedded their own versions of python to do whatever they need to do.
I wouldn't worry about it, the DLLs won't stomp on each other -- the PATH is the last placed that windows searches to find DLLs.
See: http://msdn.microsoft.com/en-us/library/7d83bc18(v=vs.80).aspx

Each DLL is for that application. There is only one in your search path so you don't need to worry about conflicts.
Is something not working that prompted you to worry about this??
Your assumption that there should only be one is wrong, each application has bundled a specific version with a fixed API, you can't just drop another in and hope it'll work.

The Python DLL naming structure only provides the major version and revision numbers. You are probably looking at the DLLs for versions 2.6.1, 2.6.4, 2.6.5, and 2.6.6.
All of this doesn't really matter as long as each application contains its own copy of the python26.dll. Windows will not explore the PATH environment variable if there is a local copy of the file.