SDII 2.8 and later allows for two mono files to be opened as a stereo pair (mainly for editing 'stereo' files created in Pro Tools). This is accomplished by giving the 2 mono files the same name, with .L appended to the left file, and .R appended to the right. If it is a single file (mono or stereo), and the file name contains a period followed by the letter L or R (for example, "Auto.Ranchero"), SDII attempts to locate the other file, which does not exist, then posts a disk error.These errors can also happen if both .L and .R files are selected when opening the files from the Finder. If you want to open a pair of split stereo files from the finder, select only one of them, not both. If the files are named properly (for example, "Music Bed.l" and "Music Bed.r"), and they are in the same folder, then only select 1 file and SDII will find the other one.Note: The .L and .R suffix is not case sensitive - upper or lower case works.