Failure to locate/load 'WebView2Loader.dll' when '#' or non-english characters in the path

[leodin61]

Description

When client app is running in a folder containing "#" character in its name, i.e. "C:\Projects\Temp\Debug #317\test.exe"
invoking CoreWebView2Environment.GetAvailableBrowserVersionString() throws:

{"Unable to load DLL 'WebView2Loader.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)"}
Data: {System.Collections.ListDictionaryInternal}
HResult: -2146233052
HelpLink: null
InnerException: null
Message: "Unable to load DLL 'WebView2Loader.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)"
Source: "Microsoft.Web.WebView2.Core"
StackTrace: " at Microsoft.Web.WebView2.Core.CoreWebView2Environment.GetAvailableCoreWebView2BrowserVersionString(String browserExecutableFolder, String& versionInfo)\r\n at Microsoft.Web.WebView2.Core.CoreWebView2Environment.GetAvailableBrowserVersionString(String browserExecutableFolder)\r\n at Nuance.Dma.View.WebView2Ext.IsRuntimeInstalled() in C:\.....\WebView2Ext.cs:line 63"
TargetSite: {Int32 GetAvailableCoreWebView2BrowserVersionString(System.String, System.String ByRef)}
TypeName: ""

Loader lib confirmed to be in place ( C:\Projects\Temp\Debug #317\x86\WebView2Loader.dll )

Removing "#" from the folder name works fine.

Version
SDK: WebView2 v1.0.705.50 (WPF)
Runtime: evergreen runtime "90.0.818.49"
Framework: WPF
OS: Win10

Repro Steps

AB#37110283

[champnic]

Hey @leodin61 - thanks for the bug report! There have been some minor changes to where and how the WebView2Loader.dll is loaded - would you mind trying a newer SDK package to see if that resolves the issue? If not I'm happy to put this bug on our backlog to take a closer look.

[gileli121]

@champnic
I found out that when the program path contains non-English characters, you will get this error
And the error is not fixed also in 1.0.1056-prerelease when running the program under a folder with a path that contains non-English characters.

In my case, I used this path:
C:\עברית\Build2

[gileli121]

@champnic
This issue with non-English characters is very old and I was able to reproduce it even with 1.0.705.50
I could not test older versions because my app will fail to build due to code compatibility issue

[champnic]

Thanks for the pointer! If that's the issue then I expect this affects all of our SDKs. I've added this bug to our backlog to try and fix.

[gileli121]

@champnic
Thanks.
Any idea when it will be fixed?
I tried these workarounds:
Win32Native.AddDllDirectory("\\");
https://docs.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-adddlldirectory

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern int AddDllDirectory(string lpPathName);

And also:
Utils.AddEnvironmentPaths(new[] { "\\" });

        public static void AddEnvironmentPaths(IEnumerable<string> paths)
        {
            var path = new[] {Environment.GetEnvironmentVariable("PATH") ?? string.Empty};

            string newPath = string.Join(Path.PathSeparator.ToString(), path.Concat(paths));

            Environment.SetEnvironmentVariable("PATH", newPath);
        }

I hoped that somehow it will pick it using a relative path that does not depend on non-English chars.
it did not fix it

[champnic]

Hey @gileli121 - Can you try using SetDllDirectory (also in kernel32.dll) instead of AddDllDirectory?

[champnic]

I've got the fix getting checked in now - I'll let you know when it's available. Thanks!

[gileli121]

@champnic
Great!
I wanted to check if SetDllDirectory will work. I did not know that this function exists. I just did not have time last day to check it.
But even if it will work, it is a less good solution for my case because I use multiple DLL directories and not only one.
And I assume that this function will remove all other DLL directories and replace them to one directory.

How did you fixed it?

[champnic]

When we were calculating the path to the WebView2Loader.dll in our code it was getting put through a new Uri(<path>) which was stripping out the # character from the path. The fix is to use the paths directly.

Ya, sounds like SetDllDirectory probably won't help you here. The other option is to manually LoadLibrary for WebView2Loader.dll yourself. but I would probably wait until the fix is available if you can.

[gileli121]

@champnic
When the fix will be available?
It is now 10 days since I reported about it

[champnic]

Hey @gileli121 - The fix will ship with the next prerelease package (it unfortunately missed the recent prerelease), which will probably be in early January. Thanks!

[champnic]

This is now fixed in the 1.0.1133-prerelease SDK. Thanks!

[Mecanik]

I have the same issue. Once I moved the .exe out of the debug/release folder this message shows. Very weird since there is no such .dll in the first place in the debug/release folders. Any ideas where I can get it?

[Mecanik]

I take one comment back, it seems the .dll is deployed to "runtimes\win-x86\native".

[champnic]

Hey @Mecanik - Your app needs some WebView2 SDK files shipped with it to function properly. There should be some helpful details here:
https://docs.microsoft.com/en-us/microsoft-edge/webview2/concepts/distribution#files-to-ship-with-the-app