On Surface RT, the microSD card reader is located under the kickstand on the right side. Tip: If you're using Surface, you can add up to 64 GB of storage with a microSD card. If you need to free more space (the drive is still marked red), go to the next tip. Go back to Computer in File Explorer, select the drive you cleaned up, and then select Refresh. In the message that appears, select Delete files. To remove data from a previous installation of Windows, select the Previous Windows installation(s) check box. In the Disk Cleanup dialog box, on the Disk Cleanup tab, select the check boxes for the file types that you want to delete, and then select OK. In the Disk Cleanup dialog box in the Description section, select Clean up system files. If prompted, select the drive that you want to clean up, and then select OK. In the search box, type Disk Cleanup, and then, in the list of results, select Disk Cleanup. Open Disk Cleanup by clicking the Start button. One of the easiest ways to clean up files you no longer need is by using Disk Cleanup. Cleaning out your PC on a regular basis frees up drive space and helps it run better.

How to clear storage on mac air