Installation Errors: Android devices
When Installing Bookshelf for Android from the Google Play Store
Any errors during the download or installation of the App from the PlayStore. You may see the error “App Not Installed” OR “Times Out during download"
You will need to refer to the Android Articles to troubleshoot Fix problems downloading apps from the Play Store - Google Play Help
When Installing Bookshelf for Windows 10 without the Microsoft Store
”For your security, your phone\device currently isn’t allowed to install unknown apps from this source. You can change this in Settings”
You will need to refer to the Android Articles to troubleshoot under the review section “Turn off getting apps from other sources” > Download apps to your Pixel phone - Pixel Phone Help (google.com) [instructions may vary depending on device manufacturer]