I’ve been having this same problem with my 5 year old Mac laptop, and they told me the CPU is going bad.

Take it back to the guy who ‘fixed’ it. Tell him to try again.

On a Mac, the hard drive space (storage) is used as virtual memory in conjunction with the physical memory (RAM) to store data being used during program and system use. It is recommended that the hard drive never reach beyond 85 percent capacity, as you begin to utilize that virtual memory space for storage of data. That does slow down performance significantly over time.

There are utility programs out there that will go through your storage and remove redundant, non-used files that are “invisible” to the user; these hidden files are often cache files that are deposited in storage and left there by apps (including web browsers) that are never accessed again. That’s what may be happening on your case.

One thing you can try is to use the search to see what files have been added on the current day, and also what files are big and might be deletable. First, empty the recycled bin.

Open the search dialog (easiest way – hold the “start key” and press “F” at the same time. Leave the top two fields empty, and for “Look in:” click on the right and select the C-drive.

For “When was it modified”, click on the down-pointing chevron on the right, then select the bottom selection “Specify dates”. It should default to today. You should now have a list of all files created on this day, which might give you an idea what is being added.

If your drive is too full, then you can select “What size is it?” instead, and pick the largest size. After the search, go to the “View” menu, and select “Details”, then select “Choose Details” and check “Size”. Then you can either select “Arrange icons by”, “size” (maybe twice to sort from biggest at the top), or click on the column heading for “Size” once or twice to get the biggest at the top. If you recognize any files that are big, and not needed, deleted them here. Empty the trash later to free the space.

If this seems too complicated, then you need help. Take the advice above, and take it back to the guy that “fixed” it.