It may have been removed, moved, or file permissions may be preventing access.

I have more hard drives than there are letters in the alphabet. So, on each machine in my network, I create a directory on it's C: drive named Net_Drives. Lets call this machine Muff. In the Net_Drives folder on Muff, there is a folder for every other remote machine in the network (8 in all). In the folder for a given machine, lets call that machine Barn, is a <SYMLINKD> for each shared drive on that remote machine. So far the path is C:\Net_Drives\Barn. In this Net_Drives folder on each machine is a batch file that creates all of the SYMLINKDs. This is the part of the batch file on Muff that creates all of the SYMLINKDs that point to Barn. MD Barn_Drives CD Barn_Drives mklink /D Barn_C~ \\Barn\Barn_C mklink /D Barn_D~ \\Barn\Barn_D mklink /D Barn_E~ \\Barn\Barn_E mklink /D Barn_L~ \\Barn\Barn_L mklink /D Barn_M~ \\Barn\Barn_M mklink /D Barn_R~ \\Barn\Barn_R mklink /D Barn_X~ \\Barn\Barn_X CD .. NET SHARE Barn_Drives=C:\Net_Drives\Barn_Drives /GRANT:Everyone,FULL /REMARK:"SymLinks to all Barn Drives" NET USE Z: \\Muff\Barn_Drives /PERSISTENT:YES After the SYMLINKDs are created in the Barn_Drives folder, C:\Net_Drives\Barn_Drives is shared with no restrictions. Then that share is mapped to the Z: drive on Muff. Result: Z: --> all drives on Barn, Y: --> all drives on .... One drive letter for each machine in the house and every machine in the house can get to every hard drive in the entire network. This is my first Firefox 60.0.2 ESR installation. I have been running on Firefox 52 ESR for more than a year. 52 ESR had no problem with the SYMLINKDs. Now, Firefox ESR 60.0.2 says: Access to the file was denied The file at /Z:/Barn_X/Videos_4/TV Shows/Series/Spangle/Spangle_Episodes.htm is not readable. It may have been removed, moved, or file permissions may be preventing access. This happens for any file with a <SYMLINKD> in the path to that file. 52 ESR had no issue with the path: Z:\Barn_X\Videos_4\TV Shows\Series\Spangle\Spangle_Episodes.htm Z: is mapped to that shared folder on the C: drive and Barn_X is a <SYMLINKD> created in that folder. I believe this to be a bug, but I don't know how to enter a bug report. Thank You