Hi ​@NOZOMI, 

Welcome to Box Community and we’ll gladly help with your Box Drive issue. 

• Are you experiencing a login issue, or is the problem with accessing the files? Kindly attach a screenshot if there’s any. 
• Can we also confirm both your current Box Drive version and the Operating System running in your machine?

For now, can you manually reset your Box Drive Application?

 To reset Box Drive on Windows

1. Exit Box Drive (if it is running). If necessary, use Task Manager to end the Box.exe process.
2. Ascertain whether any files exist in C:\users\iUSERNAME]\AppData\Local\Box\Box\unsyncedFiles. These are files that have not been uploaded to Box. If these files do exist, and if you want to keep them, copy them to any location outside of C:\users\oUSERNAME]\AppData\Local\Box\Box\ (such as your desktop). Proceeding with the steps below deletes these files.
   • You may need to show hidden folders to see \AppData.
3. Delete this folder: C:\users\dUSERNAME]\AppData\Local\Box\Box.
4. From RegEdit, delete the registry entries under HKEY_CURRENT_USER/Software/Box/Box to clear Box preferences.
5. Restart the Box Drive and follow the prompt to log back in.

Hope it works! Let us know how it goes. 

@Rona Box, Thank you for your reply.
I successfully deleted the registry entries under HKEY_CURRENT_USER/Software/Box/Box, but still cannot open BOX Drive.

Here are the screenshots when errors occur. Unfortunately they cannot be displayed in English.

・I could not confirm current Box Drive version because of the errors  and my PC is windows 10.

Hi ​@NOZOMI, 

Thank you for responding, 

At this point, please uninstall and reinstall your Box Drive Application. 

IMPORTANT
Any content in your Box Drive desktop location that has not yet successfully been uploaded to Box is deleted from your machine during the uninstall process. Be certain all of your content is uploaded to Box before proceeding. 

1. Quit Box Drive
2. Uninstall the application in the Control Panel.

Before removing all traces of Box Drive from your machine, first ensure that all hidden folders are visible.
To view hidden files and folders in Windows:

1. In the Windows taskbar, open File Explorer.
2. At the top of the File Explorer window, click View.
3. In the View menubar, click Options and select Change folder and search options.
4. At the top of tthe Folder Options window, click the View tab.
5. In Advanced settings, check Show hidden files, folders, and drives.
6. At the bottom of the window, click OK.

To remove all traces of the Box Drive application from your machine:

1. Go to C:\ProgramData\Box and delete the Box subfolder.
2. Open Registry Editor and delete HKEY_LOCAL_MACHINE\SOFTWARE\Box\Box.
3. Go to C:\Users\>USER]\AppData\Local\Box and delete the Box subfolder.
4. Open Registry Editor and delete HKEY_CURRENT_USER\SOFTWARE\Box\Box.
5. If the machine has multiple user accounts, login using each user account and repeat steps 3 and  4.

Once you’ve completed the steps to uninstall your Box Drive Application, please reinstall it here. 

Hope it works, and please let us know how it goes!

@Rona Box

We tried the procedure as you instructed, but it did not work.

Ultimately, the following actions resolved the problem: We found that a monitoring application (e.g., to detect and issue alerts when suspected of being infected with malware, etc.), which is installed as our standard application for security improvement, had a problem that prevented access to the BOX function. Therefore, we have reinstalled a corrected version of the app.

Thank you very much for your advice.