Cannot use '; file already in use Microsoft JET Database engine_ Application Tips

Error type:
Microsoft JET Database Engine (0x80004005)
Cannot use '; file is already in use.

Error Reason: Resolve: The IIS user has insufficient permissions on the data directory, LDB files cannot be automatically generated

Workaround: Add write access to the data directory for anonymous users of the Internet

Exception Details: System.Data.OleDb.OleDbException: Cannot use '; file is already in use.

This usually occurs when the Web site program accesses the database.
This error occurs for three possible reasons:
1.iis users have insufficient permissions on the data directory and LDB files cannot be automatically generated.
2. The database to be connected has been opened, occupied! Close the database to resolve the problem! (Maybe someone is downloading your database!)
3. The virtual host user, the space is full, the purchase space size already used up.
Solution:
1. In the first case, if the space is purchased, please contact the space merchant for processing; If you are a space trader or server administrator, because IIS users do not have read and write access to the database directory, the solution is to open My computer and locate the directory where the program is located (for example, D:\wwwroot\). Right click on the directory, select the "Security" menu item, select "User", the Everyone user's read and write permissions are added, OK, refresh the browser page, you can use the system correctly.
2. If there is a problem, the space provider or server administrator can restart the server. This allows the database to be consumed. If it is a virtual host space, contact the space trader to handle it. Please make sure you are not uploading or downloading the database to cause the database file to be occupied.
3. Lack of space, contact space business to increase the space or upgrade the configuration of the site.

Other relevant reference content:
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Analysis
1. Resolve: IIS users do not have sufficient permissions to the data directory, LDB files can not be automatically generated, please add Internet anonymous users write access to the data directory.
The result: Still not
2. Log off the Windows account and login again.
The result: it works, and it does seem that a process is taking up the MDB file.
Note: To determine whether an MDB file is occupied by the process, look at the same directory with the same name of the LDB file, if any, is occupied. When released, the LDB file disappears.
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Problem: Cannot use "; file already in use, Microsoft JET Database Engine
Workaround: The IIS user does not have enough permissions on the data directory, LDB files cannot be generated automatically, please add write access to the data directory for anonymous users of the Internet.

See also: Microsoft Support---Microsoft Knowledge Base Article-289681