My storage goes down drastically everyday for no reason
About every other day I get the message saying that my storage space is about used up or competely full and I should remove some files. And I know it's wrong because 1) I have not added anything new to my hard drive 2) everything I use is attached to an external HD and 3) when ever I restart my laptop, the storage space gets reset to its real used storage (about 17 gigs).
I don't know why it just started doing this. I had this laptop for almost 3 years. Does anyone know what is causing this and where all this unused supposed drive space is going?
Thanks.
MacBook Pro, Mac OS X (10.7.5), 15 in high res dis mid2010 128 hdd