Problem with Time Machine.

[DIIIGod]

I tried setting up Time Machine on my MBP a while ago with my 200 GB harddrive external, and it said It wasn't big enough... My MBP is only a 250 GB HDD, and have 103 GB free...

so why don't it let me ? Does my external have to be as big or bigger then my mbp hdd ???

 

[Weaselboy]

The external only needs to be at least as large as the total data. You would want cushion above that allow for the backup set to grow as file versions are saved.

With your example of ~150GB of data and a 200GB external... that should work just fine. Is there something else on the external drive maybe? Open Disk Utility and take a look at the free space on the external. As long as there is no data you want to keep on the external it would be a good idea to reformat it in Disk Utility to Mac OS Extended (Journaled) anyway so you have a fresh start.