diff --git a/.github/workflows/check-installation.yml b/.github/workflows/check-installation.yml
index 11761ec..721e043 100644
--- a/.github/workflows/check-installation.yml
+++ b/.github/workflows/check-installation.yml
@@ -66,7 +66,7 @@ jobs:
       - name: Modify fluent-ffmpeg processor.js
         run: |
           cat ./node_modules/fluent-ffmpeg/lib/processor.js
-          sed -i -e '/setTimeout(function() {/,/}, 20);/c\
+          sed -i -e '/^\s*setTimeout(function() {/,/}, 20);/c\
                     setTimeout(function() {\
                       if (ffmpegProc.exitCode === null){\
                         emitEnd(new Error('\''Output stream closed'\''));\