Please try out the fix according to this issue:

#541

@denfromufa
If I read well the issue #541 it seems you were saying in this issue

When I test Python calls to .NET, then the memory leak is less obvious, since all resources are released when calling the CPython gc.collect()

My issue is that gc.collect() from python doesn't release my memory.

I saw that you have a branch fixing the memory issue.

Should I try to install the pythonnet version of your branch?

Yes, try this branch developed by @dmitriyse:

#532

I also created branch https://github.com/pythonnet/pythonnet/tree/featured
With all PRs applied. I would recommend to test this branch if something goes wrong.

C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Microsoft.Common.targets(983,5): warning MSB3644: The reference assembl
ies for framework ".NETFramework,Version=v4.0" were not found. To resolve this, install the SDK or Targeting Pack for t
his framework version or retarget your application to a version of the framework for which you have the SDK or Targetin
g Pack installed. Note that assemblies will be resolved from the Global Assembly Cache (GAC) and will be used in place
of reference assemblies. Therefore your assembly may not be correctly targeted for the framework you intend.

CSC : error CS1617: Invalid option '6' for /langversion; must be ISO-1, ISO-2, 3, 4, 5 or Default

got this warning and this error when doing python setup.py bdist_wheel with your branch. Is there any quick fix I can try?

Sorry I didn't restarted my computer after installing VS I must be tired. So now I fixed this issue I got the following error

Python.Runtime -> E:\python_project\pythonnet-featured\pythonnet-featured\src\runtime\bin\Python.Runtime.dll
  Python.Test -> E:\python_project\pythonnet-featured\pythonnet-featured\src\testing\bin\Python.Test.dll
dynamic.cs(121,28): warning CS0618: 'PythonEngine.RunString(string, IntPtr?, IntPtr?)' is obsolete: 'RunString is depre
cated and will be removed. Use Exec/Eval/RunSimpleString instead.' [E:\python_project\pythonnet-featured\pythonnet-feat
ured\src\embed_tests\Python.EmbeddingTest.csproj]
  Python.EmbeddingTest -> E:\python_project\pythonnet-featured\pythonnet-featured\src\embed_tests\bin\Python.EmbeddingT
  est.exe
  Console -> E:\python_project\pythonnet-featured\pythonnet-featured\src\console\bin\nPython.exe
  clrmodule -> E:\python_project\pythonnet-featured\pythonnet-featured\src\clrmodule\bin\clrmodule.dll
E:\python_project\pythonnet-featured\pythonnet-featured\packages\UnmanagedExports.1.2.7\tools\RGiesecke.DllExport.targe
ts(58,3): error : Microsoft.Build.Utilities.ToolLocationHelper could not find ildasm.exe. [E:\python_project\pythonnet-
featured\pythonnet-featured\src\clrmodule\clrmodule.csproj]

I added to path the winsdk link to this exe but this change nothing. I am on my home machine so the operating system is now :
Operating System: Windows 10 Home 64bits.
Visual studio and .NET :
Microsoft Visual Studio Community 2017
Version 15.4.4
VisualStudio.15.Release/15.4.4+27004.2009
Microsoft .NET Framework
Version 4.7.02046

Installed Version: Community

when using --xplat option ihave the same error about ildasm.exe after it runs through .NET core

I have 3 ildasm.exe :
C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.6.1 Tools\x64\ildasm.exe
C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.7 Tools\x64\ildasm.exe
C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.6.1 Tools\ildasm.exe

it looks like this

#216

I checked the file in question and it seems it already calls the 1.2.7 of unmanagedexports
is there anything I can do to fix this in my environment or is this in the code of the module ?

I manage to install it from the following binary :

https://ci.appveyor.com/project/pythonnet/pythonnet/branch/featured/job/7daumkda8h36k89t/artifacts

this branch didn't fix my memory leak

You need to provide minimum reproducible example like I did in the linked issue above.

Ok I'll try to do that but it make take a while for me to identify one leaking element of the C# code library I use because I know very few thing about this code yet or about C# in general to begin with and this code is a simulator using multiple nested structure of C# objects.

Anyway your simple example of instancing a double in a for loop doesn't cause memory leak in my case even on the release 2.3.0 version of pythonnet. I will try to instanciate a simple example of a nested structure of C# object to see if it leaks.

I also used a temporary solution to work with until i fix the issue, I encapsulate my call to the C# library in a multiprocessing.Process.
when the process end the memory leak is cleaned with the process and doesn't propagate to the main process.

using multiprocessing.Pool, the memory leak is shared to the pool meaning if you have a lot of elements in your pool the memory leak will skyrocket pretty fast but when the whole pool end the memory leak is also cleaned

Thanks for your time.

You can also use .NET memory profiler such as one of these, but it may not work due to some unmanaged memory:

https://stackoverflow.com/a/100490/2230844

The easiest is commenting out code until the leak is narrowed down to few lines of code.

closing due to inactivity and no reproducible example

@denfromufa Since i didn't have access to the C# code i couldn't do what was suggested. Anyway i circumvent the issue migrating my code to linux with mono and dont have memory leak issues there.