Printers and scanners use tiny pieces of software called drivers to connect to your computer. Click the name of the device you want to use and then click “Add.” This scanner is now available for use. Click the plus icon at the bottom right corner of the left menu.If it does not connect automatically, re-add the scanner manually.
The final troubleshooting step when you cannot scan after upgrading to Mac OS X 10.10 is to reset the printing system.
If you are unsure how to match your scanner to an app on your computer, skip to the next step. Not all scanning devices will be associated with an app. This step is only recommended if you know precisely what app you use to operate the scanner on your computer. Go to the Applications folder on your computer and delete any existing scanning apps. Some scanning devices, such as HP models, include a scanning app.
If there is an applicable update, download it and install using the instructions from your manufacturer. Visit the website of your scanner manufacturer and search using your device model number.
If there is no update available, move to the next step. Install any pending updates that match your scanner make and model.