Ancestry online trees and Synching to FTM for Mac problem

OR… How to stop myself from tearing my hair out

I have spent the majority of today on a steep leaning curve. Though I purchased FTM for Mac v.2, about 12 months ago, today was my first attempt at uploading the changes made on FTM to my online ancestry tree.

Before doing this, I spent many hours cleaning up the FTM database; deleting unrelated people who were added by son no. 2, last year when he first started showing an interest in his family history – he added anyone with his surname that he could find. I guess I should have emphasized the need to ensure they were actually related, but I was too thrilled with his interest to interfere too much.

I also spent an extra couple of hours resolving place names, and deleting place names that had no person attached.

I used this file to experiment with, as it was relatively small with 1152 people. I reduced this today to 832. However, once synched I have noticed an anomaly. The FTM file shows the correct 832 people, while the online tree still shows the original 1152! I notice when synching that it seems to go both ways, even if the only changes were made in FTM.

What am I doing wrong? How do I get rid of those unrelated Ottery family members without doing the same process on my Ancestry Member Tree? It is easy, though time consuming, to do in FTM but almost impossible online.  One of the reasons I purchased this software was so that I did not have to repeat my research or corrections in two different places. So should I delete the online tree and upload the new and cleaner tree (I still have a bit of work to do deleting multiple facts, such as “Residence” for the same 1851 English census, which appears two or three times on various individuals)

And that is besides the irritation of the original 303 media files not downloading when I first started this process 12 months ago, and which caused my original despondency and lack of confidence in continuing with this process until now. Or do I put it away for another 12 months while my hair grows back?