I've been trying to figure out for months what modified attachments actually are, since I'll check and see there are 1,000 of them, and then check again and there are 4. Since Brain always says the first thing to do if you're having problems is check for modified attachments, seems like it would be good to know what they are.
I was finally able to get a response from Brain folks:
"From time to time, documents can be modified OUTSIDE of TheBrain. Therefore, TheBrain has no idea that it has been edited or modified in any way. Doing a sync, will not update these types of documents to the Cloud. An example of how a file can be modified outside of TheBrain:
You have a word document attached to a Thought in your Brain called Office.doc. If you open office.doc in your Brain, TheBrain will know it is being modified and everything is fine. The next day, you open MS Word and go to Recent Documents in the application and open up Office.doc to do some changes. TheBrain has no idea that this file is being modified. Next time you sync, this file will not be uploaded to TheCloud.
Running the Check for Modified Attachments will tell TheBrain about all of these outside edited docs and fix everything.
The question at hand now - why does your setting stay at 5? It should make the fixes and roll back to zero. I've successfully replicated this error (mine is stuck on 4) in house and will inform our engineers of the issue for review."
That said, the answer doesn't necessarily help. When I check a Brain and see that there are 1,000 modified attachments, when virtually all of the attachments referenced in the Brain are internal and I haven't even accessed more than a few of them, much less modified them, I have no idea what is happening to cause the attachments to be identified by the Brain as having been modified.
I'm hoping that, per the email I included, the Brain people will figure out why the # of modified attachments never goes to zero (I have one Brain with a floor of 4, another with a minimum of 12." But if anyone ever figures out why the # of modified attachments is incredibly volatile I'd love to hear about it.