diff --git a/tst/passthrough-fuse3/winposix.c b/tst/passthrough-fuse3/winposix.c
index a4b89ddc..f8468500 100644
--- a/tst/passthrough-fuse3/winposix.c
+++ b/tst/passthrough-fuse3/winposix.c
@@ -131,21 +131,44 @@ char *realpath(const char *path, char *resolved)
     int err = 0;
     WCHAR PathBuf[PATH_MAX];
     WCHAR ResultBuf[PATH_MAX];
+    PWSTR ResultBufBgn = &ResultBuf[6];
     if (0 < MultiByteToWideChar(CP_UTF8, 0, path, -1, PathBuf, PATH_MAX))
     {
-        DWORD len = GetFullPathNameW(PathBuf, PATH_MAX, ResultBuf, 0);
+        DWORD len = GetFullPathNameW(PathBuf, PATH_MAX - 6, ResultBufBgn, 0);
         if (0 == len)
             err = GetLastError();
-        else if (PATH_MAX < len)
+        else if (PATH_MAX - 6 < len)
             err = ERROR_INVALID_PARAMETER;
-        WideCharToMultiByte(CP_UTF8, 0, ResultBuf, -1, result, PATH_MAX * 4, 0, 0);
+        else
+        {
+            WideCharToMultiByte(CP_UTF8, 0, ResultBufBgn, -1, result, PATH_MAX * 4, 0, 0);
+            if (L'\\' == ResultBufBgn[0] && L'\\' == ResultBufBgn[1])
+            {
+                ResultBufBgn = ResultBuf;
+                ResultBufBgn[0] = L'\\';
+                ResultBufBgn[1] = L'\\';
+                ResultBufBgn[2] = L'?';
+                ResultBufBgn[3] = L'\\';
+                ResultBufBgn[4] = L'U';
+                ResultBufBgn[5] = L'N';
+                ResultBufBgn[6] = L'C';
+            }
+            else
+            {
+                ResultBufBgn = &ResultBuf[2];
+                ResultBufBgn[0] = L'\\';
+                ResultBufBgn[1] = L'\\';
+                ResultBufBgn[2] = L'?';
+                ResultBufBgn[3] = L'\\';
+            }
+        }
     }
     else
         err = GetLastError();
 
     if (0 == err)
     {
-        HANDLE h = CreateFileW(ResultBuf,
+        HANDLE h = CreateFileW(ResultBufBgn,
             FILE_READ_ATTRIBUTES, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
             0,
             OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, 0);
@@ -163,25 +186,48 @@ char *realpath(const char *path, char *resolved)
         errno = maperror(err);
         result = 0;
     }
-
     return result;
 }
 
 int uncpath(const char *path, WCHAR *buf, int nchar)
 {
-    if (4 < nchar &&
-        0 < MultiByteToWideChar(CP_UTF8, 0, path, -1, &buf[4], nchar - 4))
+    PWSTR BufP = 0;
+    if ('\\' == path[0] && '\\' == path[1])
     {
-        buf[0] = L'\\';
-        buf[1] = L'\\';
-        buf[2] = L'?';
-        buf[3] = L'\\';
-        int i = 4;
-        while (buf[i])
+        if (8 < nchar &&
+            0 < MultiByteToWideChar(CP_UTF8, 0, &path[2], -1, &buf[8], nchar - 8))
         {
-            if (L'/' == buf[i])
-                buf[i] = L'\\';
-            i++;
+            BufP = &buf[8];
+            buf[0] = L'\\';
+            buf[1] = L'\\';
+            buf[2] = L'?';
+            buf[3] = L'\\';
+            buf[4] = L'U';
+            buf[5] = L'N';
+            buf[6] = L'C';
+            buf[7] = L'\\';
+        }
+    }
+    else
+    {
+        if (4 < nchar &&
+            0 < MultiByteToWideChar(CP_UTF8, 0, path, -1, &buf[4], nchar - 4))
+        {
+            BufP = &buf[4];
+            buf[0] = L'\\';
+            buf[1] = L'\\';
+            buf[2] = L'?';
+            buf[3] = L'\\';
+        }
+    }
+
+    if (BufP)
+    {
+        while (*BufP)
+        {
+            if (L'/' == *BufP)
+                *BufP = L'\\';
+            BufP++;
         }
         return 1;
     }