diff --git a/Dist/install_git_hooks.ps1 b/Dist/install_git_hooks.ps1
index bfa257397a..51022a0532 100755
--- a/Dist/install_git_hooks.ps1
+++ b/Dist/install_git_hooks.ps1
@@ -2,13 +2,14 @@
 $targetDir = "$PSScriptRoot/../.git/hooks"
 if (Test-Path $targetDir -PathType Container) { # is Git repo
 	$PSCommandFilename = Split-Path $PSCommandPath -Leaf
+	$shimChecksum = (Get-FileHash "$PSScriptRoot/git_hook_shim.sh").Hash
 	foreach ($f in Get-ChildItem "$PSScriptRoot/git_hooks") {
 		$target = Join-Path $targetDir (Split-Path $f -LeafBase)
 		if (!(Test-Path $target -PathType Leaf)) { # target file doesn't exist
 			echo "[$PSCommandFilename] creating Git hook $($f.Name)"
 			Copy-Item "$PSScriptRoot/git_hook_shim.sh" $target
 			#TODO use symlinks on Linux
-		} elseif ($(Get-FileHash $target).Hash -ne $(Get-FileHash $f.FullName).Hash) { # files differ
+		} elseif ((Get-FileHash $target).Hash -ne $shimChecksum) { # files differ
 			$head = Get-Content $target -TotalCount 3
 			echo "[$PSCommandFilename] found existing Git hook $($f.Name), please resolve conflict manually"
 			exit 1