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Windows 7 USB pendrive access denied

    Question

  • If I try to read any file on any pendrive or usb disk I get Access denied.  I can do nothing, not even view in a text editor.  I have no issue in safe mode, all works correctly.  Note I can view an autorun.inf file on one USB in a text editor but that's it.

    • I've checked the permissions which are set to EVERYONE and I'm an administrator.
    • I've turned off the firewall
    • I've tried to create a new file but get access denied
    • I can create a new folder and a new folder inside that but can't create or paste a file into the folders.  The new folders are created read only and I can't turn that off (right click properties, uncheck read only, next time I look read only again)
    • I've been in registry and USBSTOR is set to 3
    • I've enabled a full administrator and tried to access the files from that account but there is no change (net user administrator /active:yes)
    • I've tried bit bit locker - nothing is locking the files
    • I've tried take ownership - no change
    • I've tried to look at the task manager for some process starting when a USB drive is inserted but can't see anything
    • I've checked the USB drives on other windows and Linux machines and they all function correctly.

    I've run out of things to find on the web.  It's a Dell precision laptop.  I do everyone MS update and I did run AVG tuneup and while ago and run AVG 2014 internet security.  I don't know when it stopped working as I now backup to dropbox

    If anybody has any other suggestions I would appreciate it greatly



    • Edited by SimonButt Tuesday, November 26, 2013 9:32 AM
    Tuesday, November 26, 2013 9:27 AM

Answers

  • Hi Balaji

    I'm not entirely sure why the autorun file on one of the pendrives was readable, it might have been the fact that it's a very small file.  The Malwarebytes was previously run and I'm fairly sure that it wasn't a malware issue.

    I've done a bit more digging and found that there was a lowerfilter on the CDROM and USB Devclass global unique identifiers.  This was CMgPCS.  I renamed the lowerFilters to OLD_Lowerfilters to deactivate them.  

    Now I have improved behaviour, I can;

    Read all files on USB Pendrives /  Harddisks, view PDFs listen to music etc.

    I can't write properly however and it works really strange this is what I do and what happens;

    1. I create a text file NEWFILE.txt on the USB drive    > works OK

    2. Open and type something in the file    > works OK

    3. Save the File

    4. Close the file

    5. Open the file  > contents still correct

    6. modify the file and save > Works OK

    7. Explorer reports a file size of > 0

    8. remove the  drive

    9. re-insert the drive

    10. Explorer reports a file size of >0

    11. Edit the file

    12. contents ar now a single line of multiple instances of the character Y with an umlaut on it

    13. Close the file 

    14. explorer reports file size of 0

    15. edit the file and there are now no contents

    I checked CMgPCS in C:\windows\System32\drivers and the file CmgPCS.sysy is a port control Driver copyright DELL and CREDANT Technologies

    I'm thinking now that this is some Dell software that has for some reason restricted my external ports

    Monday, December 02, 2013 12:30 PM

All replies

  • Hi SimonButt,

    Please check the pendrive with some other system. If you are able to transfer files to pendrive with different computer, then problem should be any virus infection. Try scanning your computer with Malwarebytes.

    Tuesday, November 26, 2013 9:49 AM
  • Hi

    Based on your troubleshooting step, seems no issue with the physical pen drive

    May I know if your PC connected to the specific network

    If not, try this step

    Start -> Run... -> gpedit.msc -> OK

    Computer Configuration -> Administrative Templates -> System -> Removable Storage Access

    disabled all of the "Deny read access/write access" options;

    Here are the ones I changed:

    Removable Disks:  Deny execute access
    Removable Disks:  Deny read access
    Removable Disks:  Deny write access

    Double-click each one and select the 'Disabled' radio button.

    Do the same as above, except the first step is "User Configuration" instead of "Computer Configuration"

    Hope it help


    • Edited by britishdhez Tuesday, November 26, 2013 9:57 AM
    Tuesday, November 26, 2013 9:57 AM
  • Hi Dinesh

    Although this found some irritating web bowser tool bars etc it didn't help with the problem

    Tuesday, November 26, 2013 11:02 AM
  • All where set to unconfigured.  

    I tried enabling them and access was then completely denied to the usb drive, no directory list or anything.

     I then set them to disable and I returned to being able to see the directory structure but still getting the access denied messages when I try to access individual files.  

    One extra thing that I have noticed is that the hot swap DVD drive works the same way.  

    It appears as if it is a genuine permissions issue with all removable storage but as admin I expect to have top level permission.

    I know that I've been spoilt with Linux root and permissions systems being more logical but I can't help but think that I'm missing something really simple.

    Tuesday, November 26, 2013 11:10 AM
  • Hi,

    Please uninstall the AVG temporarily to see if the issue is caused by it.

    If the issue still persists, use Clean Boot to troubleshoot if it exists some third-party software conflict.

    How to perform a clean boot in Windows 8.1, Windows 8, Windows 7, or Windows Vista

    http://support.microsoft.com/kb/929135/en-us

    If it finds nothing, please reset the ACLs with default inherited ACLs for all matching files:

    Icacls 

    http://technet.microsoft.com/en-us/library/cc753525.aspx


    Karen Hu
    TechNet Community Support

    Wednesday, November 27, 2013 9:30 AM
  • The issue, I guess, is that the autorun.inf file is created as a result of a malware. And since the malware file linked with the autorun.inf fails to execute due to the antivirus, the error message is displayed. 

    You can try the following steps:

    1. Right click on the pendrive in Computer->click Open or Explore and then check.

    2. If that files, restart the PC in Safe Mode, delete the autorun.inf file, restart the PC in normal mode and then check.

    3. You can try assigning a different drive letter to the pendrive, remove it and then insert it, and then check. Follow the link to change the drive letter:

    http://windows.microsoft.com/en-us/windows7/change-add-or-remove-a-drive-letter

    Additionally, run MalwareBytes and then check.


    Balaji Kundalam


    Wednesday, November 27, 2013 6:33 PM
  • Hi Balaji

    I'm not entirely sure why the autorun file on one of the pendrives was readable, it might have been the fact that it's a very small file.  The Malwarebytes was previously run and I'm fairly sure that it wasn't a malware issue.

    I've done a bit more digging and found that there was a lowerfilter on the CDROM and USB Devclass global unique identifiers.  This was CMgPCS.  I renamed the lowerFilters to OLD_Lowerfilters to deactivate them.  

    Now I have improved behaviour, I can;

    Read all files on USB Pendrives /  Harddisks, view PDFs listen to music etc.

    I can't write properly however and it works really strange this is what I do and what happens;

    1. I create a text file NEWFILE.txt on the USB drive    > works OK

    2. Open and type something in the file    > works OK

    3. Save the File

    4. Close the file

    5. Open the file  > contents still correct

    6. modify the file and save > Works OK

    7. Explorer reports a file size of > 0

    8. remove the  drive

    9. re-insert the drive

    10. Explorer reports a file size of >0

    11. Edit the file

    12. contents ar now a single line of multiple instances of the character Y with an umlaut on it

    13. Close the file 

    14. explorer reports file size of 0

    15. edit the file and there are now no contents

    I checked CMgPCS in C:\windows\System32\drivers and the file CmgPCS.sysy is a port control Driver copyright DELL and CREDANT Technologies

    I'm thinking now that this is some Dell software that has for some reason restricted my external ports

    Monday, December 02, 2013 12:30 PM