A grayed out routing folder indicates that the software identifies the network dataset as being changed.
This can occur when a data update is installed. This can also occur if the file dates/times have been changed on the map data folders.
This does not cause any issues other than a slightly longer processing time the first time the folders are used. In cases where the street data has changed significantly, the results of Build Routes can be different (i.e., longer or shorter processing times depending on the changes made). The software needs to rebuild the internal OD matrix with the drive times.