Opening solution in a new version is a horrible experience


Whenever I download a new version of Rider, either EAP or mainline release, the experience of opening a solution in the new version is horrible.

During the process of re-scanning my solution, Rider will show thousands of false errors - right now I'm looking at 5242 errors in 318 files, and the number is rising. These are errors of the type "Cannot apply indexing to an expression of type 'System.Collections.Generic.List<Foo>" and so on - completely valid code that's being shown as not compiling.

Rider also pukes several dozen exceptions during the process, and it seems like most internal systems simply gets overloaded and breaks.

The result is that ever reinstall requires me to open the solution in Rider, allow it to do all of it's errors, close Rider, and open the solution again. That'll cause the errors to rapidly tick away until none are left, while Rider pukes another dozen exceptions.

Finally, I can restart Rider a final time and get back to working like normal.

This has been consistent for every Rider upgrade that's shipped. I was assuming that this was something that would get better over time, but it seems like it's not the case. Is it simply my project that's an outlier here, or is it just expected that Rider will utterly break when opening a large project for the first time?



Could you please collect (Help | Compress Logs and Show in ...) logs, share them via  form and let us know the exact file name?


Kind regards,




Thanks for the reply. The file is:

The errors this time was less severe - 16 erroneous errors in 9 files, and only 58 exceptions (5 different exceptions that happened between 2 and 26 times).

The errors are:

- IReadOnlyList<T> doesn't resolve

- Can't resolve a call to PropertyInfo.GetValue(object), suggests the (object, object[]) overload instead

- All uses of tuples result in "Type 'System.ValueTuple' is not resolved"

Do you want me to create a bug report as well? As you can tell from the post, what goes wrong isn't in any way consistent. It seems consistent that opening the project in a new version of Rider causes a bunch of issues.


I guess this is the root cause issue
Try to disable Incremental Compiler and call Assets->"Sync C# project" to regenerate csproj files.


Also here is a corresponding issue. Please, attach your csproj file to it.


Thanks for the replies.

@Ivan Shakhov, a side-effect of the incremental compiler is that we have C# 7.3 features available in Unity. If I disable it, a large chunk of our codebase wouldn't be able to compile.

@Sofia Byzova, the project is split into dozens of csproj files. Should I upload a zip of all of them? Also, should I do it with their current state, or should I regenerate them first?


@Baste does it stop compiling in Unity or just csproj LangVersion becomes latest or 7.3?


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