Quite a few theories have popped up about why certain USB sticks are failing. I suspect that there is no single reason why these USB sticks fail, but more that different types of USB sticks are failing for different reasons.

I'll jot down the main theories here, along with links to threads where they have been discussed.

• https://gurce.net/oldforum/176-usb-memory-stick-not-detected.txt

One user reported having problems when his USB stick was formatted in Mac OSX. He then tried formatting it from Windows (7?) and it worked fine.

Other Mac users have reported that it works fine as long as you pick “FAT32” and the “MBR” option, which they said was the default for them (perhaps not for others?)

For step-by-step walkthroughs with screenshots, please take a look at the Correctly formatting your USB sticks page.

Justin Pope from the facebook group found that if you insert the troublesome USB prior to powering up, it works, but if you insert it after power up and go straight to BASIC, it doesn't. He suspects that some USB sticks take a longer time to register with the system.

Here is a youtube video he prepared describing the matter:

• https://www.youtube.com/watch?v=Y0raxpuudVA

Spannernick from the community forum reported that he had a troublesome USB stick that seemed to only work if you loaded a game from the carousel first (E.g., Alleykat or Avenger) and then jumped to basic. This seemed to not only trigger the fast-loader and D81 file support, but also got his troublesome stick to work!

For Windows users, Nicole Birgel in the fb forum suggested:

• do not to use “Quick Format”
• do a “Full Format”
• FB user Dean Le Blanc recently reported success with this method:
  • https://www.facebook.com/groups/209280506324242/permalink/330439800874978/

This report from Chad Diederichs in the fb group:

Windows won't let you format any volume over 32GB as FAT32. I had to repartition my 64GB USB drive down to a 32GB partition before formatting.

I've been assessing a failing USB stick in further detail (versus my working USB stick). It appears that the reason it was failing was that even though it was formatted as FAT32, it was formatted as an un-partitioned drive. I.e., it did not have an MBR (Master Boot Record). After formatting the drive with an MBR, the USB stick then worked.

For those that want all my technical investigation notes, find them here:

• https://gurce.net/c64mini_files/c64%20mini%20-%20USB%20stick%20FAT32%20investigations.pdf

The notes also outline how Mac OSX users can assure that they format with FAT32 + MBR.

I haven't assessed how the Windows10 formatting tool behaves as yet, but for Windows users having trouble, some users have suggested 3rd party formatting/partitioning tools that might be worth a try. I've listed a few of them in the alternative_ways_to_format_to_fat32_on_windows_10 section below.

Yes, it appears to be that way. I've investigated my troublesome USB stick with the Windows 10 formatting tool. The detailed notes are here:

• https://gurce.net/c64mini_files/c64%20mini%20-%20USB%20stick%20FAT32%20investigations%20-%20Windows10.pdf

My quick conclusion is:

• If your USB stick didn't have an MBR prior to you formatting it, then the windows formatting tool won't add an MBR
• So if you're using windows 10, don't use the in-built formatting tool, try one of the suggested 3rd party formatting tools instead that others have had success with.

For those hell-bent on doing it via the in-built windows tools, I did find a path, but it was finicky:

• Windows does have a “Disk Management” GUI tool for partitioning, but it doesn't permit you do delete volumes on removable devices such as USB sticks (you will need to do this in order to use that tool to do the “Create Simple Volume” action on unallocated USB disk space in order for an MBR to appear)
• So you can use a command-line tool called “diskpart” (run as admin) and delete the USB stick's volume, but be super-careful you're deleting the correct volume! (Wouldn't want to trash your hard-drive! :))
• After deleting your USB stick's volume, you can return to the “Disk Management” GUI tool and you will see your USB stick's drive space is now “unallocated”.
• You can then right-click it and “Create Simple Volume” (which can create a new FAT32 volume + MBR).

For step-by-step walkthroughs with screenshots, please take a look at the Correctly formatting your USB sticks page.

• SirGeldi in the community forum has confirmed that this tool works for Windows.
• User Jimbo in the community forum has confirmed that this tool also works for Mac OSX:
• I have also tested it on Mac, with success:
  • https://gurce.net/oldforum/176-usb-memory-stick-not-detected.txt

The tool is available for download here:

• https://www.sdcard.org/downloads/formatter_4/

Spannernick from the community forums recommended this tool to format to FAT32:

• https://gurce.net/oldforum/296-unable-to-update-firmware-or-play-extra-games.txt

The tool is available for download here:

• https://www.partitionwizard.com/free-partition-manager.html

Jumpmanjr from the community forum suggested formatting the USB stick from the command-line. I don't believe this method has been tested though, and I suspect that it will simply format the volume and not provide an MBR for the disk.

1. Hit the Windows start button and type: CMD and hit ENTER.
2. Type the following command: format /FS:FAT32 /Q X: (Replace X with the drive letter of your USB-stick) and hit ENTER.

I think a truly command-line method for adding the MBR will relate to using the “diskpart” tool (rather than the 'format' tool).

By default in Windows, the file extensions of a file are hidden in windows explorer.

So a file called “mygame.d64” will show up as simply “mygame”.

So when users are instructed to rename their d64 files to “TheC64-drive8.d64”, they inevitably cause the file to be renamed to “TheC64-drive8.d64.d64”.

This can be prevented by changing windows settings to show file extensions.

• Click the start button and type extensions
• Select the “Show or Hide File extensions” option and adjust it accordingly.