I have a danish character in my profile name when I log into Windows. This means %USERPROFILE% is c:\users\søren.
In ARMA 2 I could add a -profiles=C:\arma3\Profiles to launch parameters to avoid the dansih character.
I have done the same for ARMA 3 and it fails
{F17697}
Add -profiles=C:\arma3\Profiles to launch, save a game in ARMA 3 and try to reload the save game
Error message is "Cannot load 'c:\arma3\Profiles\Users\Coffee\Saved\a3\missions_f\showcases\showcase_infantry\save2.Arma3AlphaSave'.
The same thing happens for my default profile. The folder name is "S%f8ren" and ingame it is shown as "S REN"
Closing, as the ticket is very old and has not received any attention in a long time. Problem is presumed to no longer be valid.
If the issue is still reproducable for you, please create a ticket asking for this one to be re-opened.