Syncing from multiple sources

I’m sure that this has been covered in a previous post but I couldn’t find an answer - my apologies.

Firstly, I just joined and have been enjoying seeing my runs gradually appear on my life map. It makes run-exploring a city/area much more rewarding. Thanks James!

I have been syncing with Garmin, but just hit the issue that nothing from 2016 or earlier is appearing in my profile.
I wonder if I can add MapMyRun (which is synced with Garmin, and includes all runs from 2016 and earlier) - mainly I’m concerned in case activities are duplicated - is this an issue, or are duplicates vetoed based on their start times (or similar)?

Also, does this only work for GPS routes, or does it also sync actitivies where the maps were added by hand afterwards? For some time I just ran with a stopwatch - no GPS - so these routes are manual only.

Many thanks!

My understanding is that this issue is resolved.
How many days have passed since your syncing started?

Syncing skips activities with the exact same start time, so you shouldn’t see duplicates.

I’m not sure, it depends on how the service treats that data. I’ve edited activities in Runkeeper & had those edits appear properly in CityStrides… but I’ve also recently seen some manually created Runkeeper activities include broken GPS coordinates. I’m unsure what MapMyRun, Strava, and Garmin do with their data.
If the service sends me valid GPS coordinates, I use them. I’d expect that each pin you drop while creating the map would correspond with a GPS coordinate, but I can’t be sure.

Thanks James!

The Garmin syncing was proceeding for roughly a day and then appeared to stop for a day when it reached Jan 2017. In any case, I added Mapmyrun and there are no obvious duplicates yet, so this is working as hoped. Great!

FYI my activities on MapMyRun where I manually draw the route are showing as having no map. This answers my second question. It’s frustrating but no biggie (and obviously stems from MapMyRun, not from your service).