When loading up Minecraft on switch it takes atleast 2 minutes to load, with a large portion of that being a black screen and not the real loading screen, I believe it may be due to save data size because my brother loads up atleast slightly faster than me
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We're already tracking this issue at MCPE-62708, so I will resolve and link this ticket as a duplicate.
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It happens to me too, when I start minecraft on my nintendo switch it takes 5 minutes (checked on my watch) to load, my save data is 1.5gb even I have nothing, I deleted all the things I've purchased and the size didn't go down, I have even deleted the data and redownloaded it (except for the save data because it doesn't upload to nintendo cloud for some reason I don't know) and it still takes 5 mins or more to load