FSTAB Stopped Mounting CIFS SAMBA Share
Solution 1:
Given the location of your mount point I would suggest a systemd automount.
Add noauto,x-systemd.automount to your list of options:
//192.168.1.71/fs1 /mnt/FS1 cifs rw,credentials=/var/credentials,uid=1000,gid=1000,noauto,x-systemd.automount 0 0
The way this will work is that it will not mount at boot time but when the /mnt/FS1 folder is accessed. Accessed by you directly, or by a script, or by another process, or by another application ... The whole thing is rather seamless.
EDIT: For it to work though Dolphin I have to add the 'user' option to fstab:
//192.168.1.71/fs1 /mnt/FS1 cifs rw,credentials=/var/credentials,uid=1000,gid=1000,noauto,x-systemd.automount,user 0 0