How to fix a Microsoft Access database

A lot of established businesses still keep their jobs, stock, quotes or registers in Access, often in a database someone built years ago. When it breaks, here’s what to check first, which versions Microsoft no longer updates, and how to tell when it’s time to move it.

SI30 Pty Ltd, Brisbane. Updated 10 November 2026.

We fix and rebuild Microsoft Access databases for businesses in Brisbane and South East Queensland.

Database stuck right now? Call 0410 383 332, weekdays 8am to 5pm, and tell us what it’s doing.

On Access 2021 or an older one-off version? Microsoft no longer sends it security updates, though it still opens and runs. Check your version, then decide whether to upgrade, fix or move it. Outgrown it? See how we move it.

First: keep an untouched copy

Before you try any fix, make sure no one has the database open, on any computer or in any other program. Make a copy of the database file (.accdb or the older .mdb), and of the separate data file if the tables live on a server. Keep one copy untouched and work on another.

Two things to know first. A copied database can still be linked to the live data on the server, so ask whoever maintains it before you test on a copy. And a repair can quietly drop damaged rows even when Access says it worked, so before anyone uses a repaired file, compare record counts and important totals with the untouched copy.

Is your version of Access still supported?

Microsoft has stopped security updates for the older one-off versions of Access, one after another. Those versions still open and run, but they no longer get fixes. Access 2024 gets security updates until 9 October 2029, and Access in Microsoft 365 stays supported with an active subscription and updates turned on.

To see which one you have, open Access and go to File, Account (in Access 2010, File, Help). Read the product name and match it to the table. About Access shows a version number starting with 16.0 for all of the recent versions, so that number isn’t the year; it also shows whether you have 32-bit or 64-bit.

Common problems and what to try

“Unrecognized database format”, or it won’t open

1. Work on the working copy. If it opens, go to File, Info, Compact & Repair Database. If it won’t open, start Access, create a blank database, then go to File, Close (if the Open screen appears, press Esc), then Database Tools, Compact and Repair Database, and pick the working copy when Access asks for the file.
2. If that fails, create a new blank database and import from the working copy. In Microsoft 365 and Access 2019 or later: External Data, New Data Source, From Database, Access. In Access 2010, 2013 and most Access 2016 installs: External Data, Access. If you don’t see that button, use the first path. Choose Import (not Link), then on each tab (Tables, Queries, Forms, Reports, Macros, Modules) click Select All. Click Options and make sure Relationships is ticked.
3. An object that won’t import needs a closer look. It may be damaged, or it may be a link to another file, a query whose table you didn’t import, or a form from a locked .accde file. After importing, open the tables and compare record counts and totals with the untouched copy. A table whose icon shows a link keeps its rows in whichever file the link points to, usually the data file on the server.
4. The same message also appears when an older Access opens a file saved by a newer one. Check that everyone is on the same version.

Corruption usually starts with a write that was cut off: a dropped network connection, Wi-Fi, a VPN, a laptop going to sleep, or a sync folder (OneDrive, Dropbox) copying the file while it was open. Fixing the file without fixing the cause means it happens again.

“File already in use”, or locked by a user who has gone home

Access keeps a small lock file next to the database (.laccdb, or .ldb for .mdb files). If a computer crashed or lost the network, the lock can be left behind. First confirm that no person or program is using the database; ask IT if you’re unsure. Only then delete the leftover lock file. If Windows says it’s in use, something still has the database open: don’t force it. Never delete the database file itself. If it keeps happening, ask IT to check the folder’s permissions.

Slow, or freezing when several people use it

• Split it. Keep the tables in a back-end file on the server, and give each person their own copy of the front end (forms, queries and reports) on their own computer. Do this when nobody is using the database. One person copies it onto their own computer and runs the wizard on that copy, never on the shared file: Database Tools, Move Data, Access Database, then Split Database. When the wizard asks where to save the back end, choose the shared server folder by its network path (two backslashes, the server name, then the share), not a drive letter. Copy the new front end onto each person’s own computer. Rename or move the old shared file so old shortcuts can’t open it. If you move the back end later, relink the tables with External Data, Linked Table Manager before anyone uses it. From then on everyone uses their own copy of the new front end, never the old file, or you’ll end up with two sets of records.
• Use a wired office network for the back end. Opening the shared file directly over Wi-Fi or a VPN is slow and a common cause of corruption. For staff working from home, Remote Desktop or a database server is safer.
• Compact it regularly. Deleted records leave empty space until the file is compacted.
• Check the size. In File Explorer, right-click each database file and choose Properties. Each Access file has a 2 GB limit, including Access’s own system objects. A file getting close needs attention before more data goes in.

It broke after an Office update or a new computer

• Missing references: press Alt+F11, go to Tools, References, and look for anything marked MISSING. Only untick it if the database doesn’t need it. Otherwise have whoever maintains the database restore that library or a compatible one, then test on the working copy.
• 32-bit versus 64-bit: code written for 32-bit Office can fail on 64-bit Office with an error about Declare statements needing PtrSafe. Adding that word alone is often not enough, so have a developer check the code.
• “The Microsoft.ACE.OLEDB.12.0 provider is not registered on the local machine” (or 16.0): the program can’t find a matching Access database engine. It may be missing, the other bitness (32-bit versus 64-bit), or not available to programs outside Office because of how Office was installed. Ask IT to check the installation. This message alone doesn’t mean the database is damaged.
• Macros blocked: files that came from the internet or email are blocked from running code. Only unblock a database if you know and trust where it came from. Close it, right-click the file in File Explorer, choose Properties, tick Unblock if it’s there, and click Apply. For approved databases, IT can set up one dedicated Trusted Location: File, Options, Trust Center, Trust Center Settings, Trusted Locations. If your company blocks these settings, ask IT.
• The update itself: Office updates have broken Access before. If it stopped working on every computer on the same day, and the file still opens on a computer that hasn’t updated yet, the file is probably fine. Check Microsoft’s fixes for recent Access issues before repairing anything.

Tried these and it still won’t open, or the same problem keeps coming back? Keep the untouched copy safe, and call 0410 383 332 before you run another repair.

When fixing isn’t enough

Access is good at what it was built for: a handful of people in one office. Signs you’ve outgrown it:

• staff in the field or at home need it on a phone or tablet;
• more than a few people use it at once, and it keeps corrupting;
• a file is getting close to 2 GB;
• the person who built it has left, and nobody wants to touch the code;
• it runs on one of the versions above that Microsoft no longer updates.

Three common options:

1. Stay on Access, on a supported version. Move to Access in Microsoft 365 or Access 2024. With updates turned on, Access itself keeps getting security fixes. It doesn’t fix multi-user or phone problems.
2. Move the tables to SQL Server, keep the Access screens. The data sits in a proper database server; people keep the forms they know. Good for more users and bigger data. It still needs Access on each computer.
3. Rebuild it as a web app. The jobs, and the records you bring across, in a browser on any computer, phone or tablet, with a login for each person and nothing to install. This is the most work. Of these three, it’s the one that runs on a phone without Access.

Microsoft’s own Power Apps and Remote Desktop are other routes. Compare the cost and fit of each before deciding.

Not sure which fits? Tell us how many people use it and what’s going wrong. Within one business day we’ll tell you which option we’d pick, even when it isn’t us.

How we move it, with your old file kept untouched

We rebuild an Access database as a web app that works in a browser on any computer, phone or tablet, with a login for each person and nothing to install.

We’re a Brisbane software company, and it starts with the free job map. Our first meeting is free: one video call, about an hour. We map how a job moves through your business and show you where it gets stuck. You keep the map, a one-page PDF, whether or not you go ahead.

If you go ahead and you’ve outgrown Access, we:

1. go through your database with you: the tables, forms, reports and the work it actually does each day;
2. bring across the records we agree on, check record counts, key values and totals, and explain any missing or damaged data with you before you switch over;
3. build the web app around how your staff already work, with a demo every week while it’s being built;
4. keep your old Access file untouched until you’re happy with the new system.

The first stage is a fixed price, from $3,000 ex GST, agreed in writing before work starts. We plan for it to go live within four to six weeks of the go-ahead, and your staff try it on real work alongside the old database before you switch. Hosting and support are a separate monthly cost, quoted up front with stage one. Your records belong to your business. You can export them at any time. More about how we work: Business systems. More on custom software development in Brisbane.

Want to see our work first? Homified, our household app, is free on the App Store, and a morning brief we built reads our own mailboxes and sends us one email at 7:30. The rest are on Our work, with where each one is up to.

Get your free job map → or call 0410 383 332, weekdays 8am to 5pm.

Not ready to talk? Take the 1-minute job check.

Questions about moving off Access

Access database repair and support in Brisbane

We look at the file first and tell you the price before any work starts. If moving off Access is the better option, we’ll tell you.

Tell us about your database → or call 0410 383 332, weekdays 8am to 5pm.