Those trying to upgrade to the latest update for Windows 10 are finding their PC is being blocked from making the move if they have an external USB device or an SD card plugged into their machine.

Why? It seems that the May 2019 Update – which is still in the final stages of testing, ahead of an expected release in May, naturally enough (probably later in the month) – is suffering from a problem whereby all drives can be inappropriately reassigned different letters if USB devices or SD cards are connected to the PC.

As you’re probably aware, Windows gives every drive attached to a computer a letter, whether that’s an internal hard drive or SSD, optical drives, or indeed external drives such as USB sticks.

And when upgrading to the May 2019 Update, it’s possible that these drive letters can be changed, with potentially nasty side-effects.

Microsoft explains: “Example: An upgrade to the May 2019 Update is tried on a computer that has the October 2018 Update installed and also has a thumb drive inserted into a USB port.

“Before the upgrade, the device would have been mounted in the system as drive G based on the existing drive configuration. However, after the upgrade, the device is reassigned a different drive letter. For example, the drive is reassigned as drive H.”

Internal hemorrhaging

The real sticking point is that this reassignment of drive letters isn’t limited to removable hardware such as USB devices, but internal hard drives can also be affected. In that case, you can imagine the potential damage when the PC is looking for files on a certain drive which are no longer there because it has been reassigned a different letter – or indeed if your system drive succumbs to this fate, heaven forbid.

So you can understand why Microsoft has blocked upgrades in the case of computers with such USB devices attached. Those who wish to upgrade their preview version of Windows 10 can currently get around the block simply by unplugging any external USB devices or SD cards, and restarting their machine, whereupon the May 2019 Update should become available.

Presumably, the issue whereby internal drives are reassigned a different drive letter can’t occur if there are no external devices plugged in.

Of course, this problem should most definitely be solved (we would hope) by the time the May 2019 Update is released to the general computing public. The last thing Microsoft needs is another disastrous issue like the file deletion problem which hit the infamously bug-plagued October 2018 Update, particularly as Microsoft has vowed to get things right this time around.

Microsoft observed: “This issue will be resolved in a future servicing update for Windows 10. For Windows Insiders [preview build testers], this issue is resolved in build 18877 [which is still to be released] and later builds.”

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Via The Register