Q: mIs there a way to see what background tasks are running on a Mac?

Please download and install EtreCheck from http://www.etresoft.com/etrecheck

Run it and post the report here.

What version of OS X are you running?

Activity Monitor is in your Applications > Utilities folder. With it you should be able see what process is causing a lot of activity.

For more about Activity Monitor, go to > https://support.apple.com/en-us/HT201464

Launch the Activity Monitor application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad and start typing the name.

Select All Processes from the View menu, if not already selected, and also select the Disk tab.

Click the heading of the Bytes Read column in the process table to sort the entries by disk usage. You may have to click it twice to get the highest value at the top. What is it, and what is the process? Repeat with the Bytes Written column.