Network volumes, such as network attached storage (NAS) devices, Apple Time Capsules, and hard drives connected to network devices, are handled differently than drives directly attached to a Mac computer. As a result, utilities like Apple’s Disk Utility and Techtool Pro cannot perform disk verifications or repairs on these network volumes if needed.

Some network drives come with built-in tools that can be accessed through a web interface or third party software application. For example, with Apple’s discontinued Time Capsule, you can gather some information about the health of its internal drive using the Airport Utility application (/Applications/Utilities).