If you are trying to save a project (or any kind of file) to an external hard drive using a Mac and you received an error saying you do not have permission to write to the drive, you most likely have this permissions problem.
Follow along and I'll show you how to quickly remedy this.
- In Finder, click on the drive you are having issues with.
- Press CMD - I to open the Info Window on the drive.
- On the bottom right, you may have a lock that is locked. Click on it to unlock it.
- Enter in your username and password for your Mac. Most likely your username is filled in.
- On the bottom of the window there is a section that says Ignore Ownership On This Volume. Check it so you have a blue checkmark.
*If you work in a setting where you are not the only owner, you will need to adjust or add by individual permissions under the privilege section.
- Click on the lock to lock from any further changes.
- Try saving your file again.
There you go. That should've fixed the problem for you. Let me know if that worked for you in the comments below.