Greetings!
I'm running Workstation 15 on my windows 10 Pro laptop. It's a preinstall that came from Dell, and not a "clean" install of Windows 10.
I have currently six (and counting) Linux guests that can not access shared folders after the Linux guest reboots.
I'm successful in initially setting up the shared folder, and under /mnt/hgfs on the Linux guest the shares show up.
However once I reboot the linux guest, the shares disappear, even though "always enabled" in checked.
The /mnt/hgfs folder remains, its just empty.
At one point I was able to run a command in terminal, and it indicated that the shares are still there, just the GUI couldn't see them.
I have a suspicion it's something on the windows side, since every linux distro I try is showing the same problem.
So far I've tried the following distros.
Mageia 6
Opensuse 15.1
Ubuntu 19.10
Kubuntu 19.04
Kubuntu 19.10
Fedora 31 (KDE)
Incidentally, on my main desktop that runs Linux, every OS, Windows or Linux that I run as a VM has no problems with shared folders.