Could not load file or assembly 'System.Buffers, Version='


I'm getting the following exception when trying to call GetDatabase method of the MongoClient class after adding a new configuration using VS config. manager:

Could not load file or assembly 'System.Buffers, Version=, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

I installed the latest System.Buffer nuget package v4.5.1, created dependentAssembly in my app.config and Reference in my .csproj file, but I still have the same issue. For some reason it tries to reference System.Buffer with v4.0.2. Has anyone had a similar error and how did you solve it?

asked on Stack Overflow Jul 21, 2020 by Adam Jensen • edited Jul 22, 2020 by Hi Guy

2 Answers


Could not load file or assembly 'System.Buffers, Version=…'


1) use CMD(run as Administrator ) and type

 cd xxxx(xxxx\packages\System.Buffers.4.5.1\lib\netstandard2.0))


gacutil /i System.Buffers.dll

Then, when you finish it, please run update-package -reinstall under package manager console to reinstall the package.

2) you can try to change Version= to Version= in csproj file.

Besides, there is a similar issue you can refer to.

answered on Stack Overflow Jul 22, 2020 by Perry Qian-MSFT • edited Aug 27, 2020 by Perry Qian-MSFT

The easiest way is to use Nuget package manager, downgrade system.buffers to any lower version, and then upgrade it to the latest again.

answered on Stack Overflow Feb 7, 2021 by omarmallat

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