I upgrade my PR4100 to OS5 last night and I discovered I was locked out of my shares. I did reboot both my file server and my Mac and logged out and in to the device from Finder. I would get sporadic access but then it’d revert back to locking me out of the filesystem.
@goterpsgo Do you have Cloud Access enabled and is your device still Indexing content?
What is the CPU and Memory usage from the AdminUI (dashboard) and top process using the most CPU and Memory?
It’s possible that your “sporadic access” issue is related to this.
Please capture the system logs of the My Cloud device when this issue occurs again and contact support with OS 5 in the subject.
How do I know if my device is still indexing content?
CPU is currently 2% and memory is 46% of 4GB installed.
I do have cloud access enabled. Top process for memory use was mysqld; everything else was at 0% CPU.
You have to set the used SMB protocol (SMB1, SMB2, SMB3) in the network configuration of your NAS.
It’s been and still is set to SMB v3.
Indexing can be seen in the AdminUI, Mobile and Web client apps but based on your memory and CPU usage, doesn’t sound like indexing is running.
That message is not there. I’ll assume then indexing is done.
@goterpsgo I would suggest to run a Full Drive Test from the AdminUI which will take a long time and check for failing HDD. Much faster to SSH and run ‘dmesg’ command and check for bad drive sectors or support can check the system logs.
My device finished its Full Drive Test and there were no problems.
I did discover my Windows laptop has zero issues accessing all shares, files and folders. My Mac is still having the same problems as before.
I was able to access my public shares and top level/child folders via Mac Finder as soon as I logged out as a user. When I logged back in, I was locked out again to those same folders.
In the system logs I keep on seeing the following entries:
CIFS: Authentication for user [joe] has FAILED
I just put in a new password for that user. My Time Machine suddenly started working again. Hope this is the solution.
UPDATE: nope.
Hi mate @goterpsgo , found the solution 
disable the recycle bin,
It’s the issue !
Created an account to let people know
@meugloups “disable recycle” bin resolved what problem that you were having?
On MyCloud OS5,
Mounting a shared folder through SMB,
the exact same issue reported by OP,
If the recycle bin is disabled, you can access the documents and folder inside the shared folder
