Convert from Mac to Windows without loosing data or attachment

It may not be too much to ask, but the answer won't thrill you. The conversion from Quicken Windows to Quicken Mac does not carry over attachments, I'm sorry to report. 

Your transaction and historical data should transfer okay to Quicken Mac. There are some features of Quicken Windows which don't exist in Quicken Mac, such as the lifetime planner and tax planner, so any data for those features is not carried over. 

Oops, sorry I mis-read!

Then my statement about attachments not transferring is also correct in this direction. But unfortunately, transaction data for investments either doesn't transfer at all or transfers incorrectly.

I don't think it's too much to ask for Quicken to fix their converter software to allow users to move reasonably easily from one platform to the other. For some reason, their management and development teams have shown no interest in doing so over the years. I'd guess that the number of users wanting to migrate from Mac to Windows is pretty small, so they haven't deemed it a priority to work on.