Why can Windows no longer see files on Android phone's external sdcard (when connected by USB)?

[Andie708]

I have two identical ZTE Zinger phones (which run Android 4.4 KitKat). Let's abbreviate them as Z1 and Z2. Z2 has no problem when connected to a USB port of my Windows Vista pc. Z1 used to have no problem, but now my pc can no longer see any files on Z1's external sd card when Z1 is connected to the pc via a USB port. Windows correctly displays the sd card's capacity, used space and free space, but all folders and files on the sd card behave as if Android is hiding them from Windows. (Android apps on Z1 can still see them). Windows Explorer still correctly shows the contents of the Z1's "Phone" folder (which is how Android 4.4 presents the phone's internal memory to the pc), and it shows the folder named "SD card" (which is how Android 4.4 presents the external sd card to the pc) but when I enter the "SD card" folder by double-clicking it, it doesn't show any of the files or folders that are in "SD card".

I've labeled the phones Z1 and Z2 to reflect the fact that I began using Z1 about two months ago and began using Z2 only a few days ago. I suspect Z1's problem with the pc began after I began using Z2 with the pc. If this is true, maybe the problem is related to the fact that when I first connected Z2 to the pc a few days ago, Z2 installed its own copy of the device driver into Windows. In other words, perhaps Z2's device driver installation overwrote or corrupted some Z1 driver information in Windows' Registry.

I tried using Windows' Device Manager to uninstall the device driver while Z1 was connected to the USB port, and then reinstalled the driver by reconnecting Z1 to the USB port. This didn't solve the problem.

Can anyone help me get Z1 to work with my pc again? If I can only have one of the two phones work with the pc, I want it to be Z1, because I gave Z2 to my brother.

Thanks in advance to anyone who tries to help!

 

[B. Diddy]

Welcome to Android Central! That's a bit of a headscratcher. I wonder if it has anything to do with the fact that you have Vista, which is pretty outdated (and no longer getting any kind of support updates from Microsoft). Can you try connecting both phones on someone else's computer that's running Windows 7 or above?

 

[Andie708]

No, that's a good idea but I don't know of a Windows 7 or 8 pc where I could test the phones.

I would guess that if the problem is in my pc, it's most likely due to a bug in the device drivers that the Zingers installed on the pc, rather than a bug in Vista.

Perhaps if I borrow Z2 back from my brother so that I can use Windows Device Manager to uninstall the device drivers for both Z1 and Z2, and then let Z1 reinstall its driver, it might fix Z1's problem.

 

[Andie708]

I should have also said that Microsoft does still support Vista, and I install the occasional updates. Windows XP is the version that Microsoft most recently stopped supporting.

 

[B. Diddy]

Oh yes, you're correct. This site says they ended "mainstream support" on 4/10/12, but will continue "extended support" until 4/11/17. Windows lifecycle fact sheet - Windows Help

 

[Andie708]

Ah... and Microsoft's "extended support" means the only updates will be fixes of security flaws. I presume this Zinger bug is unlikely to be a security flaw, so I hope I'm right that the bug probably isn't in Windows Vista.

The main task now is to get Z1 to work with my pc again by undoing whatever caused Windows to lose access to the sdcard files. My brother says he'll bring Z2 to me tomorrow, so I'll connect it and uninstall its device driver, and then I'll connect Z1 and uninstall its device driver, and then I'll reinstall Z1's device driver. If that works, I won't connect Z2 to my pc again anytime soon.

I tried something else that didn't help: I dismounted the sdcard from Z1, connected the sdcard to the pc using a USB adapter, backed up all its files to the pc, deleted the files from the sdcard, mounted the sdcard into Z1, connected Z1 to the pc, and tried copying the files to Z1's "SD card" folder from the pc backup folder. The last step failed with an error message; I neglected to jot it down, unfortunately, but I think it was a couple of sentences that meant "access denied." (There might have also been something about the possibility of an incompatible filesystem, but on the other hand that might just be me remembering something I recently saw elsewhere.) After it failed, I restored the files from backup by connecting the sdcard directly to the pc using the USB adapter again.

A suggestion I read in another forum thread is to backup the sdcard files, re-format the sdcard, and restore the files. The person who posted this suggestion said it often works in similar situations, and that when it works the problem was a corrupted filesystem. I'll try this if uninstalling Z2's driver doesn't help.

 

[Rukbat]

Try Windows.zip for the ZTE driver. (Some nice person, probably on XDA, posted it there.)

 

[Andie708]

Can you provide more information about Windows.zip? Its webpage at Dropbox doesn't say what it does or how to use it or who posted it, and the zip file contains no documentation. For security reasons, I think it would be unwise to trust it without a lot more information.

 

[Andie708]

Today I tried uninstalling the device driver associated with Z2, but it didn't help. (After I uninstalled Z2's driver, I uninstalled Z1's driver, and then re-installed Z1's driver. But the files in Z1's sdcard remain hidden from Windows, when Z1 is connected to the pc via USB port.)

Then I tried re-formatting the sdcard, but this didn't help either. (I dismounted the sdcard from Z1, connected it to the pc via a USB adapter, backed up the sdcard files to the pc, formatted the sdcard using Windows' "Quick Format" option, mounted the sdcard in Z1, "erased" the sdcard using the erase option in Android's Settings | Storage, connected Z1 to the pc, and attempted to restore the backed up files by dragging them from the pc to the "SD card" folder.) The error message when I tried to copy the files from Windows to Z1 was: "Cannot copy xxxx: The device has either stopped responding or has been disconnected." But Z1 doesn't appear to have stopped responding and it doesn't appear disconnected; Windows can still display the files in Z1's internal "Phone" folder.

Then I reconnected the sdcard directly to the pc again using the USB adapter, so I could restore its files from the backup folder on the pc. Then I mounted the sdcard back into Z1, and now it seems to be working okay when I connect Z1 to the pc.

How whimsical.

The remaining paragraphs of this post, which I've highlighted in a green font, were written before Z1 began working okay... Instead of deleting them, I'm including them since they still have some relevance.

Is it possible that the sdcard is too slow to respond? It's a new Sandisk 16GB class 4, which I bought for $5 at Amazon. Z2 also has the same model sdcard, purchased at the same time. I think class 4 is supposed to be fast enough, but maybe the 16GB card in Z1 is defective and slower than the class 4 spec.

Before I bought the 16GB sdcards, Z1 used an old Sandisk 2GB sdcard that's either class 4 or slower. It's possible that the problem with Z1 began when I switched from 2GB to 16GB, rather than when I began using Z2, because I don't remember whether I ever successfully tried connecting Z1 to the pc after I copied the 2GB card's files to the 16GB card.

I just tried reverting Z1 to the old 2GB sdcard and it works okay; Windows can see its files. So I'm thinking the 16GB sdcard I've been using in Z1 is defective: either too slow or a hardware failure or a formatting error, but one that interferes only with Windows, not with Z1's apps' ability to use the sdcard. Looks like I need to do more research on sdcard issues, unless some kind person suggests here how to diagnose and fix the problem. First I'll try a sdcard speed benchmark app, and compare the speed of Z1's 16GB card to the speed of Z2's 16 GB card.