Mini SD card (drive) goes UNALLOCATED in Disk Management where it shows as Disk 1 (D:)

[TabletFull]

The tablet has a 32 GB micro SD card.  This card has been tested over 20 times on at least 10 different PCs and works always well and has all the date (including apps) on it.  This has been like this for over a year.

When I insert the card into the tablet, it will always show in Disk Manager as Disk 1 (D:).

When I remove the card from the slot in the tablet, Disk Manager will not show anything like second drive (no Disk 1 (D:) will be shown there).

The card is accessible most of the the time, with the Disk Manager stating Disk 1 (D:) is "Healthy".  However, occassionally, withou any observable reason, the card simply vanished and cannot be accessed.  Under such scenario, if I go to Disk Manager, it will still show Disk 1 (D:) indicating that there is a micro SD card in the tablet slot, but instead of being Healthy, is says "UNALLOCATD".

And, after some time (hours or days), it will come back as Healthy, again, without any observable reasons.

Anybody having idea What Is Going On?

Is this a Windows 10 miracle?

[kyle_b]

Someone else here mentioned the micro SD card becoming unmounted on their Stream tablet, I think it was attributed to the tablet going into sleep mode and then waking up with the card unmounted.  They had to reinsert the card to remount it which of course is a nuisance since the Stream's back cover has to be removed.  I am not sure if they found a fix, you might try searching for that thread.  If your issue is sleep related, you might try adjusting the sleep settings.  You might also look in the Windows system logs to see if an event is logged when the card is unmounted.  Also try another SD card if you have one to see if it exhibits the same behavior.

[TabletFull]

Thank you very much for the comment.  I presume that your word "unmounted" is the equivalent of what Windows say, i.e. Unallocated.

Yes, to remove the backplate, pull the miniSD out and put it back, and then restart, it helps (I am not sure whether it helps all the time).  What is more interesting is that sometimes it fixes itself, withoug pulling the card out and reinserting it.  In fact, I think that it even happened ones when I was taking a video with the table, the first one was fine (it went to the miniSD drive 😧 )but the second one was not complete, and after that this SD was Unallocated.  But then in a day, it somehow (after re-start) fixed itself.  Personally, I do not think it is the miniSD card (formatted to NSTF!) but would rather blame Windows 10 as a reason (as I recall, it never happened when the table was on Windows 8.1).  Puzzle, as it sometimes fixes itself, but I am not able to find out why ...

I have never looked at Windows system logs:  Where do I find them?

[kyle_b]

Yes, by unmounted I mean the drive letter goes away, so if the SD card appears as drive 😧 in Windows Explorer, it no longer appears and there is just the C: drive left.  You might also try another SD card formatted to Fat32 to see if it works any better than NTFS. Open Event Viewer in Windows 10.

[TabletFull]

I think that originally the microSD card was FAT 32, and that I had to reformat it to NTSF.  If the issue will continue happening, I will check with another card formatted to FAT 32.

Thanks for the link to Event Viewer.  I went there, and it is quite encompassing.  Is there any way to be able to find in this Viewer a specific event based on time/date when some happened?  I.e., if it happens again, I would record exact time, and then go to Viewer and somehow ask it to show me what happened at this particular hour/minute?