I can't see any obvious reason why the first command would work on a HDD install but not a USB version, unless the difference is the computer and not the command. (e.g. If %windir% has a space in it. Or if you are trying from different folders on different machines, and the problem is to do with the folder path.)
Since the second command works everywhere, try changing each difference between it and the other command until it stops working, and that may provide the clue about where it is going wrong.
I am not sure it makes sense to combine /n and /e either.
If you look on the default toolbar, the command we use is:
Explorer.exe /e, {sourcepath$}
This is slightly better, and we'll be changing the default having noticed the path wasn't fully qualified:
{s} and {sourcepath$} turn into the same thing (assuming they are being run from a lister, and the same folder both times) so those differences do not make sense to me.
Are you doing both on the same computer or different computers? Same versions of Windows?
Same version of Opus on HDD and USB? And are the both 32-bit or 64-bit?
What happens if you run Explorer from a Command Prompt without Opus being involved?
Have you enabled Explorer Replacement in the .ini file of the USB version? It's not on by default, but seems to be happening. Try disabling it if so.
Using the USB version on a computer that has the HDD version installed is also going to confuse things a lot, as the two versions will conflict with each other and may try to register their DLLs over the top of each other if you do things that require DLL registration (Explorer Replacement and UAC).
It's also easy to cause one version to be launched (or to open a window when it's already in the background) when you thought it would launch the other, which can confuse matters. Check the full exe path for the process in Task Manager to be sure of where dopus.exe is running from.
I tried another profile with a basic DOpus setup. It worked fine.
When I login to my normal profile, the standard DOpus "Open in Explorer" button works the first time. It then defaults to Quick Access every time after that, regardless of folder I try. Logging out and logging back in corrects the issue for the first try, then reverts back to Quick Access again.
I misspoke. When first attempting to open in Windows Explorer, Windows explorer opens to the C:\ drive. Every attempt after that opens to Quick Access.
As a reminder, I've tried the following codes:
Explorer.exe /e, {sourcepath$}
Opens Quick Access
"/windows\Explorer.exe" /e, C:\
Opens C:\ drive the first time, then Quick Access every other time
"/windows\Explorer.exe /e", {sourcepath$}
"Cannot find "/windows\Explorer.exe /e"
""/windows\Explorer.exe" /e", {sourcepath$}
Doesn't open anything
"/windows\Explorer.exe" {sourcepath$}
Opens path in new lister
"/windows\Explorer.exe" /e {sourcepath$}
Opens Quick Access
It works in one profile, but not another. How do I validate /windows in Opus?
I'm still stuck and want to resolve this without creating an entirely new Windows profile, if at all possible.