# 3.3. App not installed / Installation is blocked / install_failed_verification_failure

Probably one of the following reason

• Signature mismatch between existing ReVanced install
  • Delete that existing install
• Google play protect blocked it
  • when the play protect window popped up, click "learn more" and "install anyway"
• You forgot the GmsCore patch
  • Add the GmsCore support patch and try again
• You clicked the wrong apk
  • Double-check that you selected the patched instead of the raw source apk
• There were errors during patching
  • Look at the patching log for failed
  • It should be at the first word of the line
  • if so, look at the patch not applied guide
• You exited ReVanced manager when patching
  • Don't do that. Repatch again.
• Split APK used
  • repatch with non-split APK / full apk
• Installed in "secure folder"
  • Check if "secure folder" is enabled
  • If so, see if the ReVanced is installed in the "secure folder"
  • If so, delete the install there and try again
• Some unknown reasons
  • We need more information to know what went wrong
  • Install SAI (Play store, apkmirror) on your phone
  • After patching again, click the three-dots menu and export the APK
  • Go into SAI and select the APK you just exported
    • Look at the install failure message and search it on Google
• Artifacts left from previous install / the uninstall was not done cleanly
  • This could only happen if you have installed and uninstalled ReVanced previously
  • You will need to use ADB to fully remove the old install.
  • You can find a guide here