When using the tag to filename function, if you start with a backslash (eg. \%track%), the preview function will show it putting that file in current working directory (as I'd expect). However when you actually go ahead with the rename, it throws everything into the root of your C drive.
if you specify a file path beginning with a backslash you tell the filesystem to start in the root directory of the current drive - so far mp3tag behaves just like the filesystem tells it to treat filename and I do not see any bug.
If you want toi use a relative path, you must either use no starting backslash which would then imply a directory structure starting in the current directory which is displayed in the tag panel or use the ".." markers for "one hierarchy level up" or the starting backslash to start from the root directory.
In my MP3tag the preview does not imply a working directory as starting point for the path.
Please check again.
Yes, the construction of the target filepath seems to be not correct in all cases.
Example 1.
Depending on the current working folder ...
O:\TEST\T1
a given Format string ... \%ARTIST%
will result into new filepath ... O:\TEST\T1\Air.mp3
Example 2.
Depending on the current working folder ...
O:\TEST\T1
a given Format string ... O:\%ARTIST%
will result into new filepath ... O:\Air.mp3
Once a Format string, which starts with a leading backslash to indicate the root folder on the current working drive, begins with a drive identifier too, then the resulting filepath will be the correct one.
In the other case, without the drive indentifier, Mp3tag creates a filepath mapped under the current working folder, although the leading backslash points to the root folder.