Pressing t on mac startup
To leave safe mode, you can simply restart your Mac normally without pressing any keys by selecting Restart from the Apple menu.
Thank you so much. It looked like my Shift key was stuck, but even after making sure it was before and not later, my Mac was still booting in the safe mode. I tried used the resetting the PRAM method and succeeded in getting off the safe mode.
How to Fix Grey Screen at Startup on Mac
Thank you again for showing me the way. As long as the Mac is compatible with the operating system contained on the selected drive, your Mac will continue booting the designated operating system.
The Mac Startup Manager works great if you have a number of boot options from which to choose, but your Mac also recognizes a few additional startup keys that direct it to boot immediately from a specific source. Just as with its Windows counterpart, macOS Safe Mode should be used to help troubleshoot issues that may be caused by corrupt or incompatible software, or to help isolate software issues from hardware failures.
Keyboard Shortcuts for Mac OS X
To use it, press and hold the Shift key on your keyboard as soon as you see the Apple logo. Keep holding Shift until you see a gray progress bar appear beneath the Apple boot logo.
Keep holding the keys until your Mac reboots itself and you see the Apple logo appear and disappear a second time. At this point, you can release the keys and your Mac should boot as normal.
Continue pressing until the drive tray pops out; then release. Any of those is your cue to try Step 4.
It displays icons for any bootable discs that it sees and allows you to select one including the installation DVD. This technique is quite useful if your usual boot disk is damaged or having an identity crisis during startup.