diff --git a/tools/fsreg.bat b/tools/fsreg.bat
new file mode 100644
index 00000000..afb875eb
--- /dev/null
+++ b/tools/fsreg.bat
@@ -0,0 +1,41 @@
+@echo off
+
+setlocal
+setlocal EnableDelayedExpansion
+
+set RegKey=HKLM\SYSTEM\CurrentControlSet\Services\WinFsp.Launcher\Services
+
+if not X%1==X-u (
+	set unreg=0
+
+	if not X%1==X set fsname=%1
+	if not X%2==X set fsexec="%~f2"
+	if not X%3==X set fscmdl=%3
+	if not X%4==X set fssecu=%4
+
+	if X!fscmdl!==X goto usage
+	if not exist !fsexec! goto notfound
+
+	reg add !RegKey!\!fsname! /v Executable /t REG_SZ /d !fsexec! /f
+	reg add !RegKey!\!fsname! /v CommandLine /t REG_SZ /d !fscmdl! /f
+	if not X!fssecu!==X reg add !RegKey!\!fsname! /v Security /t REG_SZ /d !fssecu! /f
+) else (
+	set unreg=1
+
+	if not X%2==X set fsname=%2
+
+	if X!fsname!==X goto usage
+
+	reg delete !RegKey!\!fsname! /f
+)
+
+exit /b 0
+
+:notfound
+echo executable !fsexec! not found >&2
+exit /b 2
+
+:usage
+echo usage: fsreg NAME EXECUTABLE COMMANDLINE [SECURITY] >&2
+echo usage: fsreg -u NAME >&2
+exit /b 2
diff --git a/tst/passthrough/passthrough.c b/tst/passthrough/passthrough.c
index c785a24e..03b22a90 100644
--- a/tst/passthrough/passthrough.c
+++ b/tst/passthrough/passthrough.c
@@ -745,6 +745,7 @@ static NTSTATUS SvcStart(FSP_SERVICE *Service, ULONG argc, PWSTR *argv)
     PWSTR PassThrough = 0;
     PWSTR MountPoint = 0;
     HANDLE DebugLogHandle = INVALID_HANDLE_VALUE;
+    WCHAR PassThroughBuf[MAX_PATH];
     PTFS *Ptfs = 0;
     NTSTATUS Result;
 
@@ -779,6 +780,26 @@ static NTSTATUS SvcStart(FSP_SERVICE *Service, ULONG argc, PWSTR *argv)
     if (arge > argp)
         goto usage;
 
+    if (0 == PassThrough && 0 != VolumePrefix)
+    {
+        PWSTR P;
+
+        P = wcschr(VolumePrefix, L'\\');
+        if (0 != P && L'\\' != P[1])
+        {
+            P = wcschr(P + 1, L'\\');
+            if (0 != P && L'$' == P[2] &&
+                (
+                (L'A' <= P[1] && P[1] <= L'Z') ||
+                (L'a' <= P[1] && P[1] <= L'z')
+                ))
+            {
+                StringCbPrintf(PassThroughBuf, sizeof PassThroughBuf, L"%c:%s", P[1], P + 3);
+                PassThrough = PassThroughBuf;
+            }
+        }
+    }
+
     if (0 == PassThrough || 0 == MountPoint)
         goto usage;