Alright then, I used to get it to work and here are the fossil setting from my system (the only reason it doesn't work for me now is because the files are no longer there to be found on my hard disk) :-

in startup.mar there's this line :-

63 real CD D

changing that to G should be fine.

In the file ENVIRON.DAT in the Guide directory I have this :-

DSS_PLTL=lo_comp.lis
DSS_PLTL2=hi_comp.lis
DSS_DIR=D:\realsky\
GUIDE5=dir D:
CONTRAST=1500,12000
CLIP_IMAGE=1

which seems to go back a really long way... guide 5!

Changing this to G:\realsky\ should have no effect other than to change the target drive.

And the changing of it in the menu dialogue box to say G:\realsky\ too as mentioned earlier.

I'm running a coupla year old version of Guide.exe, however, so if something core has changed or something has become broken during an update, that may be it.

The google search gave only the link I found before.

NOTE that the link _insisted_ that you had to put \realsky\ with a trailing \ in the string, and that \realsky wouldn't work.

There's also the pedantic little things like "show image" needs to be ticked in the relevant dialogue, or what setting you have for field width at which they're first supposed to appear, stuff like that.

Closing and restarting Guide after any change. You don't always need to do that with Guide when resetting some settings file, but for some files, like environ.dat, you may well have to.

That's all I can think of, best of luck.

Cheers

John