The requested lookup key was not found in any active activation context

Code:
     _x64: 1
   _admin: 1
_elevated: 1

TCC  26.02.42 x64   Windows 10 [Version 10.0.18363.1082]

I wanted to delete an ISO file that I no longer needed, so I did the following;
Code:
e:\documents\win98>del "Win98 SE.iso"
Deleting E:\Documents\win98\Win98 SE.iso
TCC: (Sys) The requested lookup key was not found in any active activation context.
"E:\Documents\win98\Win98 SE.iso"
     0 files deleted       1 failed

I checked, and the ISO was mounted as drive G:, so I ejected drive G:, and tried again;
Code:
e:\documents\win98>del "Win98 SE.iso"
Deleting E:\Documents\win98\Win98 SE.iso
     1 file deleted

So, all is good now, however, what does the error message;
Code:
TCC: (Sys) The requested lookup key was not found in any active activation context.
mean when I could not delete the file?

Joe