We had an issue where a SourceTree user reported "diffs aren't working for some files". This effect was unrelated to file types or file content.
Since we didn't find the answer quickly, I'd just like to document it here: The reason may be the rather small default size limit for diffing files. It can be changed in the "Diff" tab of SourceTree's settings.
Currently, in the 3.1.3 version, this setting is in Tools | Options, under the Diff tab, and is named Size Limit (Text):
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.