Flash Drive USB error "Not Accessible" and "Needs to be Formatted"

So after my Period 4 class ended, I headed off to my spare class to work on some assignments on the Mac. My Flash Drive worked perfectly fine in, and before Period 4, then in Period 5 it wasn't working. On the Mac, during my Period 5, it said "Disk not accessible" with three options. I then tried four other computers using Windows 7 and it shown "G is not accessible - The volume does not contain a recognized file system. Please make sure that all required file system drivers are loaded and that the volume is not corrupted."
At home I plugged in the Flash Drive (using Windows 7 HP 64bit) and the same error occurred.
So I tried the following things:

• Downloading over (literally) eight useless programs that searched in the Flash Drive, and then asked for money; didn't find any files at all, or said "Disk is not Valid".
• Went into cmd and typed chkdsk d: r/.
• Renamed the portion letter.
• Deleting, then installing the drivers (unplugging then plugging the Flash Drive in).

It seems the drive is corrupt, and I am not sure if it can be fixed at all, even by the world's professionals. Not too sure, but I am hoping this can be fixed, even if I have to send it to a store to use their software to recover my files and get the off that drive asap. I have all important graphic, and science work on there. I have work that needs to be handed in around one week from today.
I never kept backups as this drive has worked with my for over 4-5 years with absolutely no problems like this.
I have switched on, and off of using Windows and Macs with this drive before too.
PS: My Flash Drive was at 80% on the capacity display, then when I plugged it in after Period 4 it turned up like this:

PSS: The drive's LED lights up, so I don't think it is necessarily "dead".


This is a very dear, and important issue for me. Thanks to all/anyone who solves this.

Hi MattJoey,

Welcome to SevenForums.

Try partition recovery with the Partition Recovery Wizard in MiniTool Partition Wizard Home Edition 7.6 Best Free Partition Manager Freeware and free partition magic for Windows 7, Windows 8, Windows Vista and Windows XP 32 bit & 64 bit. MiniTool Free Partition Manager Software Home Edition.

or TestDisk (Windows version) TestDisk - CGSecurity

A trial using these for partition recovery that should help, here: Recover a flash drive turned RAW – Partition Wizard and TestDisk.

( Read only the partition recovery portions in it. Do not attempt zero-write which I did to convert a good pendrive inaccessible for the recovery trial. You already have a bad drive. :))

I'm a little confused, which one should I use in my case?

Try Partition Wizard first. If it can see the partition, doubleclicking on it should show the files in it (as shown in one of the screenshots)

If the files are shown and you are happy with it, then "Finish". Your partition should be recovered and you should be able to access all your files.

( If you can't see the files, then try TestDisk.)

Okay, I did Partion Wizard first, good thing is is that the Flash Drive is accessible now. BUT I cannot see the files, and it says "51% used space" so I basically lost 29% of my stuff?!??!!
Also, on TestDisk it doesn't show the partion as it should in Step 7 in that tutorial.
Basically the disk works now, but I don't have part of my flash drive ATM, and it's not recognized by TestDisk nor do the files show.............
Help again, please.
PS: There is also a 8mb unallocated.

It will be hard for anyone to explain why you have "lost" (????) 29%. ( One of the cardinal rules especially in cases where Windows asks the drive to be formatted is not to run checkdisk. My understanding is that Windows makes a valiant attempt to repair but finding it impossiible leaves the files in a much worse condition. It is like trying to repair a good machine which only spoils it. When I read that you had run checkDisk, my heart skipped a beat :) and that is why I asked you to check whether all your files show.)

Anyway, now that you have access to your pendrive, backup whatever files you can to another media and then attempt data recovery.

You can try Recuva and see whether it can see the other files and recover. Recuva - Undelete, Unerase, File and Disk Recovery - Free Download

Another program is Glary Utilities. Downloads | Glarysoft (download the Slim Version(no Toolbar))

In the Privacy and Security module in it, there is a File Undelete utility with which you can scan your pendrive and recover the good files.

I stop here. Good Luck.

Well, I didn't necessarily apply chkdsk. I tried it said something about the disk is RAW.
PS: I used Recuva and it found only 9 files (233mb) but there is ~900mb on the drive. There are some files still missing, am I missing a step?
I also tried Glarysoft and it is finding only a 8mb ReadyBoostPerfTest.tmp file.

That is good.

Yes, checkdisk will not run on a RAW drive.

You can go ahead with data recovery and try your luck.

Do post a screenshot how your pendrive shows up in Disk Management now.

That may help other experts here to chip in with their ideas.

Alright, thanks for the help! You guided me from ground zero to upwards. I'll go to a Computer Tech to try and recover anything else.

Did you try Glary Utilities?