Problem here is that I can't do anything to the permissions unless I take
ownership...and windows warns about the dangers of that right there.
This is highly unusual, as in Windows XP administrators are usually granted
permission to change permissions on user profile folders, and Windows Vista
can use this as well (even tho the permissions were applied by Windows XP,
"administrators" is generic between the two, so they carry over).
If you have to take ownership, then do it, but give the administrators group
ownership, not your specific username - as long as you are an administrator
in the other operating system, this should allow things to keep working

.
Once you take ownership, grant your vista user full control by adding a
permission in the security tab.
Then, if you want, you can reboot back to XP, and take ownership from XP
giving ownership to your username in XP, and that should set things back to
the way things were, except you now have access to the folder from Vista
thanks to the permission you added earlier.
I have the same username and password on both OS's but that is obviously
not enough!
Correct, it goes by your user accounts, where are represented by a number
that is generated. Even though your user names are the same in Vista and XP,
they have different numbers, so the permissions do not apply accross
operating systems. The only expcetions are the well-known groups, such as
Administrators - they have similar enough numbers to make them communicable.
I thought about removing the security from My documents under XP but I'd
rather have My documents private.
Good idea.
Actually, I have problems with other data folders created in XP from Vista
unless I take ownership, even ones that were accessible to anyone under
XP.
Yes, this makes sense - however, in the majority of cases, taking ownership
should not be necessary, as it should let you change the permissions on the
folders without forcing you to take ownership.
Seems like Vista is a lot more security conscious than XP but some things
sure take some working out!
Actually, XP is just as security conscious; it's just that running as an
admin in XP bypasses all this security, whereas this is not the case in
Vista
