docs: troubleshooting tips for cross-account admin perms and "Microso…

…ft Edge can't read or write to its data directory" error (#2931)


Co-authored-by: Lea Anthony <[email protected]>

website/docs/guides/troubleshooting.mdx

@@ -203,6 +203,153 @@ you can make the webview background transparent using the following config:
 	})
 ```
 
+## I get a "Microsoft Edge can't read or write to its data directory" error when running my program as admin on Windows
+
+You set your program to require admin permissions and it worked great! Unfortunately, some users are seeing a "Microsoft Edge can't read or write to its data directory" error when running it.
+
+When a Windows machine has two local accounts:
+
+- Alice, an admin
+- Bob, a regular user
+
+Bob sees a UAC prompt when running your program. Bob enters Alice's admin credentials into this prompt. The app launches with admin permissions under Alice's account.
+
+Wails instructs WebView2 to store user data at the specified `WebviewUserDataPath`. It defaults to `%APPDATA%\[BinaryName.exe]`. 
+
+Because the application is running under Alice's account, `%APPDATA%\[BinaryName.exe]` resolves to `C:\Users\Alice\AppData\Roaming\[BinaryName.exe]`.
+
+WebView2 [creates some child processes under Bob's logged-in account instead of Alice's admin account](https://github.com/MicrosoftEdge/WebView2Feedback/issues/932#issue-807464179). Since Bob cannot access `C:\Users\Alice\AppData\Roaming\[BinaryName.exe]`, the "Microsoft Edge can't read or write to its data directory" error is shown.
+
+Possible solution #1:
+
+Refactor your application to work without constant admin permissions. If you just need to perform a small set of admin tasks (such as running an updater), you can run your application with the minimum permissions and then use the `runas` command to run these tasks with admin permissions as needed:
+
+```go
+//go:build windows
+
+package sample
+
+import (
+    "golang.org/x/sys/windows"
+    "syscall"
+)
+
+// Calling RunAs("C:\path\to\my\updater.exe") shows Bob a UAC prompt. Bob enters Alice's admin credentials. The updater launches with admin permissions under Alice's account.
+func RunAs(path string) error {
+    verbPtr, _ := syscall.UTF16PtrFromString("runas")
+    exePtr, _ := syscall.UTF16PtrFromString(path)
+    cwdPtr, _ := syscall.UTF16PtrFromString("")
+    argPtr, _ := syscall.UTF16PtrFromString("")
+
+    var showCmd int32 = 1 //SW_NORMAL
+
+    err := windows.ShellExecute(0, verbPtr, exePtr, argPtr, cwdPtr, showCmd)
+    if err != nil {
+        return err
+    }
+    return nil
+}
+```
+
+Possible solution #2:
+
+Run your application with extended permissions. If you absolutely must run with constant admin permissions, WebView2 will function correctly if you use a data directory accessible by both users and you also launch your app with the `SeBackupPrivilege`, `SeDebugPrivilege`, and `SeRestorePrivilege` permissions. Here's an example:
+
+```go
+package main
+
+import (
+	"embed"
+	"os"
+	"runtime"
+
+	"github.com/fourcorelabs/wintoken"
+	"github.com/hectane/go-acl"
+	"github.com/wailsapp/wails/v2"
+	"github.com/wailsapp/wails/v2/pkg/options"
+	"github.com/wailsapp/wails/v2/pkg/options/assetserver"
+	"github.com/wailsapp/wails/v2/pkg/options/windows"
+)
+
+//go:embed all:frontend/dist
+var assets embed.FS
+
+const (
+	fixedTokenKey = "SAMPLE_RANDOM_KEY"
+	fixedTokenVal = "with-fixed-token"
+	webviewDir    = "C:\\ProgramData\\Sample"
+)
+
+func runWithFixedToken() {
+	println("Re-launching self")
+	token, err := wintoken.OpenProcessToken(0, wintoken.TokenPrimary) //pass 0 for own process
+	if err != nil {
+		panic(err)
+	}
+	defer token.Close()
+
+	token.EnableTokenPrivileges([]string{
+		"SeBackupPrivilege",
+		"SeDebugPrivilege",
+		"SeRestorePrivilege",
+	})
+
+	cmd := exec.Command(os.Args[0])
+	cmd.Args = os.Args
+	cmd.Env = os.Environ()
+	cmd.Env = append(cmd.Env, fmt.Sprintf("%v=%v", fixedTokenKey, fixedTokenVal))
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	cmd.SysProcAttr = &syscall.SysProcAttr{Token: syscall.Token(token.Token())}
+	if err := cmd.Run(); err != nil {
+		println("Error after launching self:", err)
+		os.Exit(1)
+	}
+	println("Clean self launch :)")
+	os.Exit(0)
+}
+
+func main() {
+	if runtime.GOOS == "windows" && os.Getenv(fixedTokenKey) != fixedTokenVal {
+		runWithFixedToken()
+	}
+
+	println("Setting data dir to", webviewDir)
+	if err := os.MkdirAll(webviewDir, os.ModePerm); err != nil {
+		println("Failed creating dir:", err)
+	}
+	if err := acl.Chmod(webviewDir, 0777); err != nil {
+		println("Failed setting ACL on dir:", err)
+	}
+
+	app := NewApp()
+
+	err := wails.Run(&options.App{
+		Title:  "sample-data-dir",
+		Width:  1024,
+		Height: 768,
+		AssetServer: &assetserver.Options{
+			Assets: assets,
+		},
+		Bind: []interface{}{
+			app,
+		},
+		Windows: &windows.Options{
+			WebviewUserDataPath: webviewDir,
+		},
+	})
+
+	if err != nil {
+		println("Error:", err.Error())
+	}
+}
+```
+
+If you use a data directory accessible by both users but not the extended privileges, you will receive a WebView2 `80010108 The object invoked has disconnected from its clients` error.
+
+Possible future solution #3: [run WebView2 using an in-memory mode if implemented](https://github.com/MicrosoftEdge/WebView2Feedback/issues/3637#issuecomment-1728300982).
+
 ## WebView2 installation succeeded, but the wails doctor command shows that it is not installed
 
 If you have installed WebView2, but the `wails doctor` command shows that it is not installed, it is likely that the
@@ -213,3 +360,4 @@ Source: https://github.com/wailsapp/wails/issues/2917
 ## WebVie2wProcess failed with kind
 
 If your Windows app generates this kind of error, you can check out what the error means [here](https://docs.microsoft.com/en-us/microsoft-edge/webview2/reference/winrt/microsoft_web_webview2_core/corewebview2processfailedkind?view=webview2-winrt-1.0.2045.28).
+