In a normal string, try doubling the backslashes in your paths. For example, ’\Users\Desktop\AICSTest.tif’ becomes ‘\\Users\\Desktop\\AICSTest.tif’. Python interprets a single backslash as an “escape” character and is trying to interpret “\U” as a special thing. Your “r” string would have worked but I believe was missing the C: drive designator, as Jianxu mentioned. You should then be able to load files from your desktop.
