For the last two days I've been trying to reproduce the issue(s) steff has reported with my NAS. So far, I haven't been able to reproduce it like steff encounters it. steff if you don't mind I'd be interested to know more about your setup you're using in your testing, e.g. routers/switches being used, if you're using a gigabit (or higher) network, wired or wireless, the method accessing your NAS (CIFS/SMB1, AFP, NFS, SMB2, SMB3, etc.) and anything else that might help replicate this. I think the more information there is, the better chance there is to understanding the possible cause.
I reproduced the issue both at my home and at work with totally different hardware.
It happens both with wired 1 Gbps network and wireless b/g/n/ WiFi
Happens with media files stored on the local NAS and also stored on another Windows 10 PC that exports shares.
THe NAS, as already mentioned, is a HPE Proliant server running Ubuntu and SAMBA, with Gigabit Ethernet
Copy to NAS and read from NAS using windows Explorer or measuring the speed with IOMeter, uses all the available bandwidht ( about 100 MByte/second )
THe PC is a standard HP EliteBook with touch screen where Microsoft Defender is running but MC executable is excluded together with the library and the NAS folder. No AV running on the Ubuntu
THe switch is a managed Netgear professional switch.
Switching to the environment at work...
the NAS is a EMC Unity running Unisphere OS, no AV at all, build on full flash technology
The switch is a Cisco 3850, 1 Gps each port
PC is stadard HP PRoBook, 1 Gbps
Some considerations:
Antivirus
If I include media extensions to the AV scaning, I really see an heavy downgrade in the performance, high CPU usage and so on. For this reason MC executable folders, remote NAS share and local library folders are excluded from scanning. No improvements if I completely disable real time protection, so... I keep Defender running real time protection, but excluded the above folders.
Media files type
16 bit \ 44 kHz FLAC, ripped from my CD collection
up to 24 bit \ 384 kHz FLAC from several music store. Even some DSD\DXD files. Up to 1 GByte size.
THe bigger the file, the longer last the issue because it takes more time to load into memory.
Test cases 1
NAS disks are sleeping and playback from memory DISABLED
I navigate the MC library, choose what to play, hit play.
THe issue starts and end as soon NAS disks are live and data are transferredn from NAS to PC; let me say... from 10 to 20 seconds
Test case 2
NAS disk are not sleeping, memory playback DISABLED
NO major issue using both small or very big media files
Test case 3
NAS disks are not sleeping, memory playback ENABLED
I choose from the library a very big 1 GByte FLAC or DSD and I hit play
THe problem starts and ends as soon MC starts to play, meaning the file fro the NAS has been completely loaded into PC memory.
How to reproduce the issue with the GUI
In test case 1, while disks are coming alive OR
in test case 3, while MC load files into memory
If I "touch" the screen of the PC, then the MC window overrides and expands to 100% of the screen, becomes blurry, out of focus, the Windows taskbar appears (if in theatre view) and the Windows pop up asking to "wait or close" appears.
THis hapens in normal view and theatre view.
If I do not touch anything... and just wait, keeping my hand firmly on the table and not on the mouse, keyboards, etc. then no problems.