I have a map with several hundred topics and sub-topics, the latter containing paragraphs of text. Most of these have multiple icons and tags from different icon and tag groups which I have used to code the sub-topics, based on their content. I use power filters to more clearly display patterns and correlations within these topics, which represent survey answers (use I know there are programs specifically for this task like Nvivo, but this would be overkill for this project and besides MM provides a good visual representation).
The problem is that I can while away the hours quite happily applying different combinations of icons and tags through the power filter and the map will remain quite stable. However if I save it after doing this the map is often corrupted and MM refuses to reopen it. The backup map may or may not be OK, depending on when it was last saved.
The obvious workaround which I have resorted to is to make a copy of the original map and use this to do the filtering. The problem is that often in playing around with the filters you can discover a topic that was incorrectly coded or you want to make some other change to the map. This means you have to make a note of these changes so you can apply them to the original map as there is a chance that changes to the map copy could be lost if it is corrupted when saved.
Am I alone in this or have other people experienced the same problem?