In order to unmount SD card, Please go to settings on your cellphone.
02. Find Storage on the settings and then select Unmount SD card to remove.
03. Now go back to Google Play Store and try to install or update the app that has a problem.
04. If it’s working, we need to re-mount SD card. Please go back to Settings > Storage > Re-mount SD card.
05. If you still get the error code 907, Please try the next method.