Nas540 not showing in Network after firmware upgrade

Swedef

Hey,

So after the latest firmware (V5.21(AATB.3)C0) uppgrade the Nas540 disapeared from Network in all my computers (they run win 7,8 & 10) I have checked all the "normal stuff" as showed in these vids:
https://www.youtube.com/watch?v=_vki_bx4zjI
https://www.youtube.com/watch?v=IbuFMXWyjn0
My settings were correct from the beginning.

I have no trouble logging in the web gui (all settings look normal), downloading torrents work fine, I can access the nas as normal on Android phone (both zcloud and vlc), Apple tv and my TV-box (android).

The first time i did the firmware uppgrade it seemed to halt on 99% forever so I rebooted it and it fired up as normal showing V5.21(AATB.3)C0 as firware version but with nas gone from network I  manually installed the same Firmware again, this time without it halting at 99%, also rebooted PC (win7 over cable) and all seemed to work normal, Nas showing in Network as normal but at next PC start it was gone again and when checking on to laptops (win8 &10) the Nas was gone there to.

I'd like to try a firmware downgrade but I'm unsure on how to do it as I have no experience in SSH or Putty 
Can anyone help me with an "Idiots guide" on how to do it please?  :-/

( I apologize for weird language or any misspellings as english is not my first language but I do hope you understand my problem)


#NAS_Nov_2019

Mihawk

So, your NAS540's firmware version is V5.21(AATB.3)C0 now?
And your problem is that you cannot find your NAS540 in your PC (Windows 7, 8 and 10)?
May I know how do you to find/access your NAS540 and got nothing? Is there any steps or screenshots?

Swedef

@Mihawk
-Yes, you are correct about my current firmware version.

I can not find it under my Network (as I did before), nor can I map up a network drive, 

I can access it in Web Gui and everything seems normal there, my brother has same Nas and his is working fine(he is using an older firmware version though), we have compared all settings we can find in Nas, PC and router but can't find anything odd there, 
Last night I checked traffic in Wireshark and to my surprise there is absolutely no SMB traffic when trying to access the Nas although lots of SMB traffic if I for example connect from my stationary pc to a Laptop.
SMB2 is active in all PCs tested.

Not shure what you want me to take a screen shot of :-/

Also when I tested last night I could suddenly find the Nas under my Network in the Laptop runing W10 (I have updated the stationary from W7 to W10 but without any change as to find the Nas, not clean install though that will be the last I will attempt)

drives me nuts...