When you open a document with a Lisa application, there must be enough
disk space to retain the original document while you work - in the event
you later choose "revert to previous version." Even more disk space is
required to enable you to use "undo." This is why you may see the
message "Not enough room to open file" when you try to read a Lisa 2.0
document stored on diskette by Lisa 7/7. If this happens, move the
document to the hard disk, where you are likely to have more free storage
space. You should then be able to work on your document with no problems.