1. Check to ensure you have permission to save to the disk or location you are attempting to save in.
2. Check if you are running out of space on your hard drive or if your hard drive is almost full.
3. Make sure that you are attempting to save the file in a compatible file type or that the program you are using supports the file type.
4. Check if the file name you are attempting to save meets the guidelines for accepted characters or length.
5. If you are saving files from a networked environment, try entering the network parameters manually or disconnect and reconnect.
6. Backup all of your important files to an external hard drive or cloud service.