I wonder if anyone here might have run into this before? I've tried everything that Google search results offer to me, no luck yet. Anyone have any ideas about this one?

Problem:
- Logging into remote desktop of work PC using an RDP client.
- Local client is an RDP program running on either Mac ("Microsoft Remote Desktop") or Windows ("MSTSC.EXE").
- Remote work PC is running Windows 10.
- Successfully connect to work PC from RDP Client.
- Open a Finder or Explorer window on your local client PC, right click on a text file, and press COPY.
- Open an Explorer window on the work PC's remote desktop.
- Right click on the remote PC's explorer window and try to press PASTE
- Can't press PASTE because it's grayed out.
- The reverse also doesn't work (copy a file FROM the remote desktop TO the local PC, this also fails the same way).
- This USED TO work fine for this PC, and then corp tightened up security on this machine. So it might be due to some kind of Group Policy setting or some other kind of security on the remote work PC. For all of the other tightening that they did on this machine, I have been able to work around all of it by finding the correct registry entries and overwriting those whenever they changed. Since my account is still Local Admin for the thing, I can still do pretty much anything I want, I just haven't found the specific local setting for this one yet.

Other diagnostic points:
- Copying and pasting TEXT always works fine between the local and remote PC, the issue is only when doing it with FILES.
- Copying and pasting files on the SAME computer works as expected in both the local and remote environments.
- The same steps work fine when connecting to other remote desktops, such as connecting to the remote desktop of another different windows computer, both home and work computers. This problem is specific to this single work computer.
- The issue is inexplicably intermittent. Sometimes pasting files to the computer WORKS on rare occasions. The rare occasions when it works, there doesn't seem to be an obvious reason why.
- I have no problem accessing the remote work PC's hard drive across the network (sharing its C drive and connecting to \\pcname\sharename). I can copy and paste files that way just fine. So that's a workaround I have. It's just annoying that I can't copy/paste files directly in the RDP session like I used to.

It is not unique to a specific user account:
- Logged in to different account on the remote work PC (logged into .\LocalAdmin on the work pc instead of corp\afabris on the work pc).
- Both of those accounts are called out specifically in the Remote access settings as being allowed to connect (and they do connect).
- Both of those accounts are in the local machine administrators group anyway.
- Did not fix the issue.

It is not unique to the RDP client:
- Logged in via a different RDP client (logged in from Windows MonkeyFlip MSTSC instead of from my Mac "Microsoft Remote Desktop")
- Did not fix the issue.

It doesn't matter if I log into the computer by hand first.
- Tried to log in to the work computer physically first.
- THEN try to RDP into the computer.
- Did not fix the issue.

Checked the remote desktop CLIENT settings for the connection:
- Make sure the "redirect clipboard" setting is active (it is).
- Go into the "Folders" settings screen.
- Tick the tickybox "Redirect Folders"
- Also tried: Adding mac hard disk ("/") to the list of redirected folders.
- (Settings above are Mac version, there are similar settings in Windows MSTSC.)
- Did not fix the issue.

Lots of internet sites say to kill and restart the remote desktop clipboard service:
- From an administrator command prompt on the remote work PC:
TASKKILL /IM Rdpclip.exe
TASKKILL /IM Rdpclip.exe
rdpclip.exe
- Did not fix the issue.

Group policy settings:
GPEDIT.MSC
Computer Configuration
Administrative Templates
Windows Components
Remote Desktop Services
Remote Desktop Session Host
Device and Resource Redirection
"Do not allow Clipboard redirection” - Set to Disabled
"Do not allow drive redirection" - Set to Disabled
- Did not fix the issue.

Tried this: http://woshub.com/cant-copy-paste-via-remote-desktop-rdp-clipboard/
reg add “HKEY_LOCAL_MACHINE\Software\Microsoft\Terminal Server” /v “DisableClipboardRedirection” /t REG_DWORD /d 0 /f
reg add “HKEY_LOCAL_MACHINE\Software\Microsoft\Terminal Server” /v “DisableDriveRedirection” /t REG_DWORD /d 0 /f
(Note: the "Terminal Server" section of the registry did not exist at first. Maybe the woshub.com web site got it wrong?)
- Did not fix the issue.

Tried this: http://woshub.com/cant-copy-paste-via-remote-desktop-rdp-clipboard/
Check the PERMISSIONS on C:\windows\system32\rdpclip.exe
- Did not fix the issue. (was already set correctly)

Tried this: https://learn.microsoft.com/en-us/troubl...on-isnt-working
Make sure the Network Providers entry has at least the default entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\NetworkProvider\Order\ProviderOrder
Default entries: RDPNP, LanmanWorkstation, web client
- Did not fix the issue. (was already set correctly)

Tried this: https://support.macincloud.com/support/s...cincloud-server
In the remote desktop CLIENT settings for the Mac version of the app:
Open Microsoft Remote Desktop.
From the main menu, click on "Microsoft Remote Desktop" > "Preferences".
Uncheck "Use Mac shortcuts for copy, cut, paste and select all, undo and find"
- Did not fix the issue.

In the remote desktop CLIENT settings for the Mac version of the app:
Open Microsoft Remote Desktop.
From the main menu, click on "Microsoft Remote Desktop" > "Preferences".
"If folder redirection is enabled for RDP files or managed resources, redirect:"
(Mac Hard disk) i.e., "/"
- Did not fix the issue.