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Access Denied to Sharepoint folders and files and open with explorer error message

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We are getting many errors when trying to access files and folders on SharePoint Libraries.

- When we try to open a file with a valid link, we get the error "Problem with Shortcut" The drive or network connection is unavailable

- When we try to open a folder with a valid link, we get the error: "Access denied" With message - file:// is not accessible.

- When we go to the web interface, select the library and try to Open with Explorer, we get the error: "Your client does not support opening this list with windows explorer"


Then after trying several things, it works fine for a while until it stops again at least every day.

One of the things I tried and that works most (but not all!!!) of the time is to go to the web interface, open and edit a document and save it back to the sharepoint server. Then, I can click on Open with Explorer, and it works. Then I can open my file and start working normally!



Is there some settings missing?

Is there an easy, quick and consistent way of re-connecting to sharepoint so that the windows explorer interface works without all these aggravations and time lost?




Alan Guggenheim

Verified Answer
  • First of all, I totally agree that this is something MS has to address in future releases for a permanent solution. But for what it is worth, here are some observations and actions I have done regarding this problem.

    From my experience there are two main causes for problems users are experiencing accessing files stored on SharePoint through mapped drives. This is off course after all initial setup is done, like steps stated in KB2629108. The Office 365 Desktop Apps Setup program will most of the time do all this for you.

    A)     The WebClient service is not running. My solution to this is setting the “startup type” for this service to “automatic”. It is a mystery to me why this modification isn’t more emphasized. Microsoft states in their troubleshooting document (KB2629108) that this service should be started, but does not mention to change the startup type to prevent the problem to reoccur. Am I missing something? Is there any drawback here that I am not aware of?

    B)      Missing authentication due to timeout of token. The problem here is that there is not valid Office 365 authentication (Form Based) method connected to the Windows Explorer. Unlike in the case of on-premise SharePoint where an authentication windows pops up when needed, Windows Explorer now only offers a frustrating error message when authentication is lacking. I have found only two methods for providing authenticating for Windows Explorer and mapped drives. The “open in explorer view” in SharePoint being the first and the Open dialog in Office being the other

    I have no golden bullet for this, but my best solution is to tell the users to open files on the SharePoint sites from an Office program (such as Word) when an Access Denied situation occurs. Because, unlike the Windows Explorer, the Office programs are fitted with Form Based authentication capabilities through the Office 365 Desktop software. If the token is still valid the authentication happens automatically, or else a normal login form appears. The beauty is that after this authentication, the mapped drives are also authenticated. Please note that it is not enough to just open an Office file directly or authenticate to SharePoint or Portal, you have to use the Open dialog in Office and browse to the file located under “SharePoint Sites”. To me it seems like this operation “injects” a browser authentication into the WebClient. The SharePoint Workspace also gets authenticated after this and the annoying “Authentication Required” messages goes away.


    Best of Luck!


    2 out of 2 people found this post helpful.

All Replies
  • Hi Alan,

    The mapped drive issue has been around since the beta, your best bet is to use Sharepoint Workspace if you have it, or just plan on remapping the drive every day. Goodnews is that the new version seems to have solved the problem.

    1 out of 1 people found this post helpful.

  • I agree with Robert. The new version of Office Pro Plus has Skydrive Pro. You can integrate with Windows Explorer, connecting to your Sharepoint libraries and allowing drag and drop of files.

  • Thanks. Is that version released? How do we get it?

  • Hello Alan

    The version Robert and I mention is Office 2013 Preview.  It is a pre-release version of the next wave of Office products and services.

    I haven't seen a release date for it yet, or when it will be available to the Office 365 population.

    Some rumours are putting the release date at early next year.

  • Hi Alan,

    How are the things going?

    In addition, do you need further assistance on this issue?


    Kevin Cui

  • Kevin,

    Thanks for the follow up.

    Things have not improved. The most pressing issue is that I have several files now that do not download.

    Alan Guggenheim

  • Hi Alan,

    I’d like to clarify with you about the thread you posted previously. Has the issue been resolved?

    If the previous issue persists, please try the following steps for further troubleshooting:

    1. Click Start icon, then Run, input “services.msc”. Click ok. Restart the “WebClient” service.

    2. Add your team site to the “Trusted sites” location of the browser.

    3. Clear the browser cache.

    After, if you still experience the problem, please provide the screenshots about the issue. It would be of great assistance.


    Kevin Cui

    0 out of 1 people found this post helpful.

  • Kevin,

    Thanks but:

    1- This is hapening on all our computers

    2- The proposed steps do not fix anything

    3- All other posts and answers by Microsoft support I have seen tend to point toward a known issue with Sharepoint 365 server side and Mapped drives. It seems to be fixed in an upcomming 2013 version!

    I found a very convoluted way to make it work, but my users hate it:

    1- Go to 365 admin site and login (I don't know why, but it is logging us out eventhough we tick the remain connected box)

    2- Go to Team site

    3- go to a shared library

    4- open a file (document, spreadsheet,...)

    5- Click on edit mode

    6- Edit the file (any change)

    7- Save the file. It should upload to the server. Verify by looking at the bottom bar

    8- Close the file

    9- Click on Library

    10- Click on Open with Explorer. This should work and open (finally...) your Windows Explorer (mapped) view

    11- If this fails, try also the following:

    12-Click on Sync to Sharepoint workspace and let it sync

    13- Click on Connect to Office and add to sharepoint sites. It should tell you the library exists already

    14- Click on Connect to Outlook and accept the warning, let it sync

    15- Click on Open with Explorer... It should work, if not...repeat from 1

    Alan Guggenheim

  • Hi Alan.Guggenheim,

    This is Jonis from Microsoft SharePoint Online Support.

    SharePoint Online for Office 365 was designed with strong two-factor authentication to improve security by requiring users to meet two authentication criteria, a user name/password and a service security token.  The design provides a high degree of security, continuity, privacy, and adherence to compliance policies and controls.

    While SharePoint Online authentication provides a high degree of security, customers have posted the same issues you described in your post.  For this reason, I am pleased to read the opinions from Robert Edward and Darrell Webster of Olympic Software NZ concerning future releases of SharePoint Online and the possible resolution of this issue.

    When you login to the SharePoint Online Portal, this process creates a SAML security token that is valid for its 8 hour lifetime.  To extend the lifetime of the Portal SAML security token to 12 hours, select the Keep Me Signed In option.

    When you connect to a SharePoint Online site using a mapped drive or Open with Explorer, you must first navigate to that site from the Admin Portal.  This process creates a site security token session that is valid for its 2 hour lifetime.  As the user continues to work with the site, new security token sessions are created every 20 minutes.  If a site is inactive for over 20 minutes, the LogonTokenCacheExpirationWindow will not reissue a new token session and the user will be logged out of that site. The SAML token for the admin portal is not affected by this process and is still active for the remainder of its 8-12 hour lifetime.

    I will continue to monitor this thread for a few days and will reply to any additional posts or questions.

    2 out of 2 people found this post helpful.

  • Jonis,

    Thanks that is interesting information.

    I understand the idea, and I agree with the principle, but the implementation seems flawed;

    First the "Keep me logedin" prompt is misleading, as it does not say anywhere that it will be only for 4 extra hours. The result is that, for the average user, it seems to never work.

    Second, and more importantly, what you describe does not work: it is not enough to "first navigate to that site from the Admin Portal.  This process creates a site security token session that is valid for its 2 hour lifetime". When you just "navigate", for some reason, the security token is not created or some part of the security exchange is not working.

    I would accept a process that says:

    1- Login to the portal

    2- Click on team site

    and then you can work on the PC Windows explorer for 2 hours... But that is NOT working.

    You have to define what "work with the site" means, because it is unclear.

    What is missing, then, is an easy interface to enter a password or any other information when we need to re-create a security token to re-activate a connection that is not working.


    Alan Guggenheim

  • Hi Alan.Guggenheim,

    If you navigate to the team site by clicking on team site, some of the examples of working with that team site include: downloading files, uploading files, viewing files, editing files, moving files or creating files.

    Because this is not working as described, I recommend that you review and implement the configurations detailed in the following article on How to use the "Open with Explorer" command and how to troubleshoot issues with this option in SharePoint Online for Office 365.

    In order to get Open with Explorer to work correctly on my Windows 7 operating system, I had to lower my UAC.  I had to set it one from the top: Notify me only when programs try to make changes to my computer and Don’t notify me when I make changes to Windows settings.

    To learn more about Windows UAC review the following article detailing User Account Control in Windows 7 Best Practices.

    If you are using mapped drives, the following link details How to configure and to troubleshoot mapped network drives that connect to SharePoint Online sites in Office 365 for enterprises.

    I will continue to monitor this thread and will reply to any additional posts or questions.

  • Hi Jonis,

    I confirm that none of the examples of "working with the team site: "downloading files, uploading files, viewing files, editing files, moving files or creating files" works: they do not reset or create the needed security token, The only way I found is to edit and save a file.

    Yes, I know the documents you mentioned, I have studied and applied them several times in the past, with no success.

    Still no good solution.


    Alan Guggenheim

  • As I've posted numerous times, the authentication system in use for 365 is too complicated and rarely works as expected.  Almost every user seems to run into this problem at some point and it's amazing it hasn't been addressed. 
  • Hi Alan.Guggenheim,

    This sounds like a trust issue, as the resolution involves opening a file from an online document library on the client desktop and then saving an updated version back to the online site.  If you have a SharePoint Online for Office 365 Professionals Small Businesses plan, it is important to note the following statement taken from the following article: Step 1: Plan sites and manage users


    To continue troubling shooting this issue, I need to replicate your environment as close as possible.  Please detail the following: internet browser version, operating system, and device type.

    I will continue to monitor this thread for a few days and will reply to any additional posts or questions.

  • Jonis,

    Thanks, but all these are very basic things that we covered months ago. The documentation does not help as it does not cover the what if it does not work scenario.

    Our 365 is not the small business version, but the Enterprise anyway.

    Internet browsers: all PC have IE 9 and have auto update.

    OS is 7, some Vista and some XP. All behave the same (poorly)

    device types: What do you mean? PC and laptops

    Yes, you can call it a trust issue, but is is probably mainly a key exchange protocol issue. There are unexpected time outs, and there is no good way to re-establish the trust. This seems like a flawed design or implementation to me.

    It works for a one time use, but not for permanent regular use.

    Plus the Workspaces still have synchronization/downloads issues. Maybe connected?