Access reports that databases are in an 'inconsistent state'

We have been able to gather additional data about the causes of this issue, which are due to usage patterns in the Access Database Engine with networked files that did not cause issues with previous versions of Windows, but no longer work properly. On Windows 10 specifically, this issue is first noted when using version 1803.

Important:

July 9, 2020 update: We have not been able to fully deploy the fix due to new issues that occur only when the fix is present. We are continuing to work on the problem.
November 29, 2019 update: The fix is being is being tested more broadly. It will be most effective when used in environments that are uniformly using Current Channel builds of Office 365, and may not fully resolve all issues. Even once this fix is fully deployed, we will continue to investigate further potential issues, and possibly update other versions of Access with the changes. Although we have identified the primary cause for the new issues that began occurring with a Windows update, we still cannot reliably reproduce the issue in a controlled environment, so ensuring that there are no additional issues is difficult. If you report the issue to Microsoft, please include as much information as you can about the circumstances under which you see errors.
July 1, 2019 update: We have been testing a fix for this issue but have discovered problems as currently written. We are working to resolve these issues and will then engage in further testing.
April 4, 2019 update: We are testing a fix for this problem now and will give further updates when we can confirm that this resolves the issue.
Due to the complexity of this issue and the need to ensure that we aren't introducing any additional problems, the release process for this issue will span more time than a typical fix. Please continue to monitor this page for further updates.

ISSUE

When opening a database, you may see the following error message:

"Microsoft Access has detected that this database is in an inconsistent state, and will attempt to recover the database."

If using DAO to open a database from Visual Basic code, you may see error 3343 “Unrecognized database format” reported.

This may happen when you have a database stored on a network file share, and multiple users are using the database simultaneously.

STATUS: WORKAROUND

The engineering team is aware of and working to fix this issue. In the meantime, disable the leasing on the machine where the shared database is stored as a workaround.

Single file database The leasing change is made on the machine where the database is stored.

Split database When using a split database scenario, where each user has their own copy of the front-end database stored on their client machine and a shared back-end database on a file server, the leasing change only needs to be made on the machine hosting the back-end database, no changes are needed to each user's client machine.

To do this:

Click Windows Start and then type Command. Right-click on Command Prompt and choose Run as administrator.
Copy and paste the following commands into the command prompt window:

REG ADD HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters /v DisableLeasing /t REG_DWORD /d 1 /f

NET STOP SERVER

NET START SERVER
Close the command prompt window.