If you are having trouble opening a text file across platforms, try saving your document as a Rich Text Format (.rtf) document. To do this, select the "File" menu in your word processing program, and select "Save As." In the "Save As" dialogue box underneath the "File Name" box, there is a "Save as Type" box. Select Rich Text Format (.rtf), type in your file name, and click "Save." Your document will now save as a Rich Text file.