I download the source code from github.
And use the command KeePass.exe" --plgx-create .\KeePassRPC to complie the plugin with KeePass 2.5.8. It’s OK.
But when I start the KeePass, the error message appears.
Why and How?
Check the build scripts (in the csproj files) to ensure you are building it correctly.
If so, maybe your file system has some permissions set which prevent KeePass from accessing some part of the plgx file (or prevent it from extracting it to the temporary compilation location). Try with other plgx files and make sure no other plugins are present and conflicting.