[Samsung Galaxy Tab A series Questions & Answers] Winston Churchill:
This might be the stupidest question ever, but has anyone else had total difficulty getting Windows to read the external SD card in their device when directly connecting their Tab A device to their PC via USB?

My device is new...it worked once registering my storage partition in Windows and hasn't again. Things that have happened since then: I updated to latest firmware with March 2018 painful security updates. May be no correlation but I thought I'd mention it.

As I was waiting for OEM unlock, I hadn't activated my ext4 partition but it still wouldn't work in Windows via USB....the card works FINE in Windows directly - I've taken it out of Samsung and put it directly into to my PC and Surface Pro and it reads storage fine. My partition software detects the app partition as well.

Then, I rooted with SuperSU/TWRPed and modded.....app partition activated successfully with Apps2SD and linked some data to it fine with Link2SD. No problems..... can't remember if I was getting the "corrupted" message I am now getting from Samsung then... I think maybe? Regardless, internally, both partitions were/are working just fine. On Windows it works fine as a stand alone card. But when I plug it in via USB inside my Tablet, I only get "Tablet" storage. This is driving me nuts. What's the point of that?

Then I switched to Magisk and the fun really started. Now, it shows what I appears to be my ext4 app partition as "corrupted" in Settings > Storage. It isn't by the way - it still works with my apps fine and the whole card is working fine (and I've run diagnostics on the card too). I have to add though, whether this was doing it between mount scripts and switching to Magisk I'm not 100% sure, it might have been.....but it's definitely there now. It's almost like it just doesn't like ext4 and doesn't really doesn't like those Mount Scripts.

Today I also reformat/repartitioned the card and did another slow error scan. So from scratch... the card is FINE as far as I can tell. This time it wouldn't mount at all since switching to Magisk. I've got it to mount through TWRP... so we're back working again. My ext4 app partition is working again with Link2SD but I'm still getting that annoying "corrupted" message in Settings > Storage WHEN IT ISN'T.

Is there some hidden settings somewhere in the stock ROM of 7.1.1 to change on the T380? Usually my devices let me pick from MTP, USB mass storage etc.... this one doesn't. It just connects to either Windows or my Surface and internal storage only.

I don't know what I'm really talking about... but it's almost like the system doesn't like that app partition... once it activated and had the Mount Scripts on it.... it was worse saying it was "corrupted" (when it isn't). Then we get back to my original problem which is getting the damn Fat32 to show up in Windows in the first place without having to take the card out of my tablet and plug it directly into Windows.

Any ideas? Thanks.

P.S. I even uninstalled and reinstalled all Samsung drivers.....dunno what to do

P.P.S. Could be an unrelated thing, but since masking everything from Samsung, when I do go to Settings now at some point between opening Settings and getting to the Storage section, I get a popup "SysScope has stopped" (or something similar). I'm not sure what that is.... but it's obviously trying to sniff around what I'm doing but I've blocked it. I doubt that's related to Fat32 and Windows, but wondering if its related to its dislike of my ext4 partition?