This will be more difficult if the Access database is on a different computer.
SQL Server runs as a service. By default, when you install SQL Server, the log on account for the sql server service is set to "Local System". The local system account does not have permissions to other computers on the network.
In order to set up a linked server to an Access database on another network computer, you'll need to make sure that the logon account for the SQL Server service has permissions.
On the SQL Server computer...
Click Start -> Run
type: services.msc
scroll down to SQL Server
Right Click -> Properties
Click the "Log On" tab.
If your sql server is configured for "Local System Account", you will need to change this. Be aware that changing this will require you to restart the SQL Server service. Restarting the service doesn't usually take long (a minute or 2), but all connections to the server will be stopped, and nobobdy will be able to access it while the service is restarting. Also be aware that all of the table data SQL Server had cached in RAM will be cleared from RAM when you restart the service. The result of this is that your database may appear to run a little slower after it is restarted while it is re-loading that cached data back in to RAM.
Anyway....
I always recommend that people create a special windows active directory account specifically for SQL Server. You'll want to make sure that account has full permissions to the SQL Server computer, and only enough permissions on the network that you absolutely need. For example, the account you create should only have permissions to the folder where you have your Access database.
-George
Microsoft SQL Server MVP
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