Error on program launch: Could not load file or assembly 'CefSharp.Core.Runtime, Version=90.6.50.0, ..... a program with an incorrect format.

[dmiddents-accesso]

The full error is
"Could not load file or assembly 'CefSharp.Core.Runtime, Version=90.6.50.0, Culture=neutral, PublicKeyToken=40c4b6fc221f4138'. An attempt was made to load a program with an incorrect format."

I've got this utility running without problem on dozens (hundreds?) of PCs. It was installed on some new PCs today. Which are in the UK - it shouldn't make a difference, but is the only thing "special" about this install. The program won't start and writes the error above to the Windows Event Viewer.

It sounds like I've got a 32bit vs 64bit mismatch. But if that were the case, the program shouldn't run at all. I tried coping only 64bit DLLs to the program directory (rather than having the files picked up from the Runtime directory). No difference. Any ideas?

Thanks,

[amaitland]

What version of .Net is your application built using? For .Net Core and .Net 5/6 you'll get this error when Microsoft Visual C ++ is missing from the machine.

https://docs.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist?view=msvc-170#visual-studio-2015-2017-2019-and-2022

[dmiddents-accesso]

@amaitland - that's exactly what the problem was. The redistributable was installed, and we are up and running. Thank you!

[amaitland]

Great 👍 Easy fix.

I've added a new FAQ entry at https://github.com/cefsharp/CefSharp/wiki/Frequently-asked-questions#NetCoreBadImageFormatException