I have been integrating EVM(43 version) in 43 version of substrate. while adding files to runtime module i am getting sys error while building it .I want to know how to solve this errorenter image description here

  • What do you mean 43 version? Jul 25, 2023 at 5:27
  • here i am referring it the branch (polkadot-v0.9.43) and same for Evm frontier branch (polkadot-v0.9.43) Jul 25, 2023 at 5:47

1 Answer 1


There is something wrong with your imports, check your Cargo.toml.

As an example if you check this previous StackExchange issue: file not found for module sys.

It worked using the default-features = false in pallet_session instead of features = ["historical"]

  • 1
    it was similar to that i have missed writing default-features false in one the pallets Aug 24, 2023 at 5:39
  • I also got the same error. But cannot understand what you explained here. could you please explain a bit more about how to solve this issue? Oct 10, 2023 at 9:49

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