Do I have to restore my Mac if I've forgotten the admin password? I've got an external hard drive which I've hooked up to time machine, I have multiple Mac's but the one in question I am unable to remember the administrator password, which is a pain when trying to create an extra user account and install software, etc.

What should I do in this situation? What's the best way of keeping all my files and existing software but be able to start up with a new user.

PS: Worst case scenario is to restore the iMac  and getting all my files back, ncluding Microsoft Office (if I am correct Time Machine will automatically back up software as well?) but is there a way of setting up the mac once restored through TM keeping all the files but not the user profile.
You can restart the Setup Assistant by performing the following:


Boot into Single User Mode ⌘ + S.
Mount the drive by typing /sbin/mount -uw / then ↩ enter.
Remove the Apple Setup Done file by typing rm /var/db/.AppleSetupDone then ↩ enter.
Reboot by typing reboot then ↩ enter.
Continue setup, making sure not to transfer data.
Setup a new administrator account. You can use this account to reset the password to the original account (through System Preferences → Users &amp; Groups).




The new account can then be deleted once the original account has been recovered.