COM Port Changing

[StellaRoberts]

We have a USB device that only works on COM9. I have set it to take COM9 in
device manager, but sometimes takes COM3. When it is assigned to COM3 it
shows that it is set to be assigned to COM9 in the advanced port
settings. I have also verified the device entries in regedit are associated to PortName
COM9, but still unsure why the device attaches to COM3. I am using a packaging
machine that is a clone of the golden image. OS is Win 10 LTSC 1809. App Vol Agent
2.15.0.41. Any insight into this issue would be greatly appreciated!

[Ray_handels]

Are you using a writable volume?

If you attach the appstack to a machine that does not have an Appvolumes agent do you see the settings in the registry regarding this device?

When you look at how your desktop is being build up it is GI --> first atssigned appstacks --.appstacks --> last assigned appstack --.> Writable.So if any of the appstacks or the writable has a different setting it will overwrite it.

[LukaszDziwisz]

Ray,

I will join that conversation and it is my coworker who started this discussion. We are using Writable Profile Only option. Based on what you are saying it appears that whatever setting we change on the appstack that consists the application that should be using that COM9 port we would have to make the same change to any other appstack that is attached to the same VM/User?

The way we are setting it up is that we attach the USB device to the physical computer and then we are opening up a console to the packaging machine on that physical computer and attaching   usb device then going to Device manager and changing the com port of that device to com9 then we seal the package

After it is being pushed to the user and the device is plugged in all the time, it looks like it is taking COM3 but if unplugged and plugged back in it takes the correct COM9 port. Is there any way to hardcode it somehow so it is always staying on COM9?

[StellaRoberts]

Hi Ray_handels,

Thank you for your response! The AppVols agent is on our image so I am not able to attach the appstack to a machine without it. I did remove my account from writeable volumes completely and the USB device is consistently connecting to COM3 and is also showing COM3 in the registry! Please let us know if you have any suggestions on how I might resolve this issue or the best practice for mapping a device to a specific COM port when using writable volumes and UEM?

[Ray_handels]

I will join that conversation and it is my coworker who started this discussion. We are using Writable Profile Only option. Based on what you are saying it appears that whatever setting we change on the appstack that consists the application that should be using that COM9 port we would have to make the same change to any other appstack that is attached to the same VM/User?

No, what I am saying is that if you have a setting for that specific COM port and during working with it it changes it to another COM port, this setting is being created within the writable, and that always wins.

You said that you are changing a registry key, where is the key located? My guess would be somewhere in the HKLM right? If it is in the HKCU you cannot add it to an appstack because appstacks only hold machine info, no user info. So anything within the HKCU reg and within c:\USers is not added to an appstack.

The AppVols agent is on our image so I am not able to attach the appstack to a machine without it

Yes you can, just create a new machine without installing the Appvolumes agent (we have a very basic machine with just W10 on it) and edit the machine by adding an existing disk. Than browse to your appstack and attache (non persistent, the disk is read only). This way you can check what settings are in the appstack. If it is indeed a registry key it should be inthere.

It could off course well be that the key or setting is stored in a location that is being excluded by Appvolumes due to exclude keys within the snapvol.cfg. When you attach the appstack to that machine make sure to also open up the snapvol.cfg so you can check what's being excluded