I can’t switch from Windows 10 to MacOs

As the title suggests, I can’t switch from Windows 10 back to macOS. I’ve tried both methods (holding down alt key while restarting, going to the boot camp icon in the task bar). One gives me an error message, something about not being able to find the OSX volume. The other comes up with the lock. I understand that, I know my password to it. However, there is a loading symbol over part of the lock and I cannot click the space to enter my password in. Help?