Off line images appear on line after reboot

Yesterday, when I opened my referenced file catalog, all of my images were "Off Line." Replacing the database with a backup of the cocatalogdb database in the cocatalog package usually restores function when a database has become corrupted. In this case, it made no difference. Images remained Off Line. I tried clicking on an older backup and the previous edition of C1 20 opened and invited me to register my product, which was itself odd. I dragged the database file onto the icon of the current version and it opened, but still the images were Off Line. 

My next step was to try to reconnect with the drive where the referenced files are located, but when locating the drive on which the files were located, C1 started locating each folder and file one file at a time. I force quit rather than waiting hours to reckoned each file. 

Last, I rebooted the computer, opened C1 and mirable dictu the referenced files now appeared on line. Of note, before this, the hard drive on which the referenced files are located did not have any obvious activity when opening the database until I rebooted. Thereafter, it did a lot of reading, as is usual, while the database loaded. 

So, if this happens to you, first reboot. Sometimes, C1 is working as it should, but the OS and C1 are not paying well together and odd things happen.