Scanning from printer/scanner combination units can be difficult because of compatibility issues, software limitations, inadequate technical support, and lack of knowledge on how to properly set up and use them. In order to scan something, the computer must be able to recognize the printer/scanner as a device and have the appropriate driver installed. Many multifunction units lack support for newer operating systems, so they may be incapable of recognizing and working with them. Additionally, printers/scanners that come packaged with all-in-one software, such as those common in multifunction units, may not be robust enough to provide the features users need or want. This can make it difficult to produce satisfactory output when attempting to scan. Poor technical support may render some units useless as any issues that arise may be unable to be resolved due to an unhelpful company or slow response time. Finally, users may not be knowledgeable enough to configure the printer/scanner properly or troubleshoot any problems. Without proper setup and understanding of the unit, scanning may be impossible.