I just went through this as well. Did a full backup of my old s5 and restored it to the new phone and then failed to register Steps on the new phone for 3 days while finding time to take it into a store, get the Sim activated on the new phone, old sd card moved to new phone and so on. Using the beginnings of the above instructions, I hooked up my old phone to wifi in the house. Went to (...) Setting. Went to Samsung account. Hit Sync there (old phone still.). Upon looking at the new phone (now with a sim card and 2 days of step data recorded on it since activation) ALL the step data, both what I had recorded on the new phone since activation yesterday, PLUS the missing three days' data from before I activated the new phone is now present on the new phone. No sync required on the new phone, and none of the post-swith data deleted or lost. No uninstall or re-activation of samsung account required! Hope this proves helpful to someone!
Thank you so much for taking the time to post this solution. A long time Samsung user, I just switched to a pixel 3a as I was tired of all the extra junk apps I didn't want and could not remove. I have been using Samsung health for years with my Galaxy watch. You can imagine my disappointment when the past year of data didn't pull through. I had no clue that the app didn't sync after all this time. I didn't have to delete or change my password, just synced on my old phone and reinstalled on the new. Thanks again
Hello, I solved the same issue but on version 6.6.0.029 where is just enough to Sync old phone manualy and then Sync on new phone.
So I did not need to uninstall from new phone nor change Samsung password.
I had Automatic sync turned off on old phone as well as on new phone. When I did sync old phone for the first time it showed me that it did sync until date a year ago. So I made sync on new phone and older data than year was there. So I repeated sync on old phone and then it showe actual date. Another sync on new phone and hurray I have all the data on new phone.
So maybe Samsung already solved the issue