Some Google apps are failing to install on Android 11 when you try to sideload the latest versions from a trustworthy source like our own sister site APK Mirror. Ever since Google released the new Android OS, "The new package couldn't be installed because the verification did not succeed" (INSTALL_FAILED_VERIFICATION_FAILURE) error keeps popping up for some people who want to install the most recent version of the Google Camera or the Google Recorder, for example.
We've found that the Play services appear to be the culprit, as uninstalling and reinstalling them on multiple phones permanently allowed us to sideload Google apps again. The Play services handle most of the APIs apps can hook into and provide notifications, security verification, location data, and so on, so it's no surprise that you could experience problems with sideloading if something is wrong with the Play services.
Some people also report lasting issues following a reinstall of the Play services such as missing notifications and battery drain, prompting them to factory-reset their phones. Proceed at your own risk.
1. Uninstall updates to the Google Play services
To uninstall all updates to the Play services, go to your phone's settings and search for "Google Play services." Tap the exact match in the results, then the three-dot overflow menu in the top right corner, and select "Uninstall updates." You'll have to confirm a scary dialog that says that "all data will be removed," and then you should be all set.
If you can't uninstall the Play services, head to the security section in your system settings, then look for the Device admin apps section and uncheck "Find my Device" there — you don't even need to reactivate it when you're all set, as "Find my Device" doesn't need to be an admin to work.
You'll have to re-enable Google backups for your account and set up your cards on Google Pay again. As mentioned above, you'll also lose all randomized COVID-tracing keys stored on your device.
2. Reinstall the latest version of the Play services
You can easily reinstall the latest version of the Play services from the Play Store. Just follow the link in the widget below on your phone and hit the update button (you won't find the Play services by searching the Play Store). Once that's done, try installing the current version of the Google Camera or the Google Recorder from APK Mirror. You might need to restart your phone first, though.
Update the Play services, activate your backup, and re-add your payment cards.
If this still doesn't work for you, try going through all the steps again, but clear the Play services data manually after you've downgraded to the pre-installed version. If that still doesn't do the trick, you might even have to get the latest release of the Play services from APK Mirror, in case the Play Store installs an older variant for you.
We're still not exactly sure what causes the problem, but it appears that this workaround allows most people to reliably sideload Google apps on Android 11 again. It's possible that there were compatibility issues with Android 11 and some version of Play services, and only a fresh install of the package is the way to bring it into working order again.
If you'd rather not go through these steps because you don't want to re-add your Pay cards, reactivate your backup, and restart your COVID-tracing, you'll have to wait until the latest versions of the Google apps hit your phone through the Play Store. It's possible that a future update to the Play Services will fix the sideloading issues for everyone, so you can only keep trying to sideload updates as they come in.