Version mismatch error WinSCPnet.DLL (5.9.1.0)

Hello,

We have been using WinSCP version 5.9.1.0 since past 1 year and it has worked fine all this while. Suddenly, it has started to report intermittent errors as below

winscp.exe () does not match version of this assembly WinSCPnet.DLL (5.9.1.0)

We haven't changed anything in the code. We also have another application using WinSCP.exe and it is also referencing the same version. Both these applications have been working fine up until last 2–3 weeks.

As mentioned, it is intermittent and does not occur frequently. some of the info as suggested in the guidelines are here:

Version of WinSCP
Dll version
No upgrades performed what so any.

Windows Server 2008

SFTP

Please attach a full debug log file showing the problem (using the latest version of WinSCP).

My services are also intermittently encountering this error.
Checking the source code for WinSCPnet, I find that it is using FileVersionInfo.GetVersionInfo to retrieve the version information of the exe.

I checked the source of FileVersionInfo.GetVersionInfo, and it checks for the existence of the file and validates permissions, both of which didn't trigger any error. It eventually calls the Windows API method GetFileInfoVersionSize, which can return 0 if an error occurs. However, GetVersionInfo itself does not check for any errors if GetFileInfoVersionSize returns 0 (as recommended by the documentation of GetFileInfoVersionSize), and so we can see a plausible scenario where FileVersionInfo.GetVersionInfo can quietly return a version info object with null properties.

If the above is the case, I'm not sure what the best approach would be to mitigate this issue, or how to find out what caused GetFileInfoVersionSize to return 0 in the first place. We should be able to replicate the error if we can find a way to reliably force GetFileInfoVersionSize to return 0 for a valid exe.

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UPDATE – A potential fix?:
An alternative to using FileVersion.GetVersionInfo for version checking would be to use Process.MainModule.FileVersionInfo.ProductVersion, i.e., we do version checking only after calling _process.Start().

donnr wrote:

My services are also intermittently encountering this error.

Can you post a debug log file for both successful and failed run?

We enabled debug logging at one point but it kept on being overwritten every time a new session is opened. As of now, debug logging is disabled in production and the soonest we can have it reenabled is on the February service release.

I'm having this issue as well. It appears I get this error randomly. I installed your package via NuGet and I am sure .dll and .exe are same version.

@starnet: We need debug log files, as mentioned above.