Data Source Excel replacement doesn't work for large files

[sferabolli]

I have a dashboard with 2 data sources:

Source A - is smaller (300 rows, 31kb), used in a blend as an outer join. Whenever I go to added Data Sources and replace the smaller one with its newest version (same name, same format, etc), it allows me to replace no problem, and the same data source updates.

Source B - larger, contains transactional data (400k rows, 40mb). When I try to do the exact same thing with the large set, the replace source process never finishes, leaving me with the old version always. 

I have tried a bunch of things: removing and re-adding the source, clearing cache, doing outside company VPN, nothing seems to work.

Is this issue known? Does anyone knows how to solve it?

tyvm!