Your .mdb database needs to move. It's either broken in your current Windows environment, at risk from the next upgrade, or simply hitting the scalability limits of the Jet engine. The question isn't whether to migrate — it's where.
Three paths are available: convert to .accdb (staying in the Access ecosystem), migrate the data to SQL Server (keeping or replacing Access as the front-end), or use the hybrid approach (Access front-end with SQL Server back-end). Each one is the right answer for a different type of database.
This guide gives you the decision criteria to pick the right path for your specific situation, without overselling either the complexity of SQL Server or the limitations of .accdb.
Before choosing a migration path, you need to understand your database's profile:
Run LegacyLeaps's free scan to get the application complexity picture: VBA module count, form count, linked table dependencies, ActiveX controls. That tells you how expensive a SQL Server migration would be relative to a simple .accdb conversion.
The .mdb to .accdb migration is the lowest-risk, lowest-cost path. Your application stays intact. Your forms, reports, and VBA code continue working. You fix Windows compatibility. You get the ACE engine instead of Jet, which provides better 64-bit support and improved security features.
What you don't get: SQL Server's enterprise security model, unlimited scale, row-level locking, or full T-SQL. For most Access databases, that's fine. The 80% of Access databases that serve small teams doing departmental work don't need SQL Server — they need to stop failing after Windows upgrades.
Migration effort: Low. LegacyLeaps automates the conversion, VBA updates, and linked table refresh. Most databases convert in hours.
Ongoing cost: No additional licensing. Access is already licensed as part of Microsoft 365.
Moving fully to SQL Server means replacing Access entirely as both the data engine and (usually) the application layer. This is the right answer for databases that have genuinely outgrown what the ACE engine can provide.
What SQL Server gives you: row-level locking for high concurrency, no file size limits, enterprise backup and recovery, full T-SQL for complex queries, integrated Windows authentication, and compatibility with Power BI and other enterprise reporting tools.
What it costs: SQL Server Standard is approximately $3,900 per 2-core pack (or Server+CAL licensing). But the real cost is development. Your Access forms, reports, and VBA code don't move to SQL Server — you need to rebuild the application layer in something that can connect to SQL Server: a new Access front-end (hybrid, see below), Power Apps, .NET, or a web application. Budget 40-200 development hours depending on complexity.
Migration effort: High. Use Microsoft's SQL Server Migration Assistant (SSMA for Access) to automate the data migration. Plan manually for the application layer rebuild.
Ongoing cost: SQL Server licensing + developer time for the application rebuild.
The hybrid approach is the pragmatic middle path. Your .mdb or .accdb becomes a shell — it still contains your forms, reports, and VBA code. But all the data tables move to SQL Server. Access connects to them via ODBC linked tables.
This is actually how Microsoft recommends Access for multi-user production use. Access handles the application tier. SQL Server handles the data tier. You get SQL Server's concurrency handling and backup infrastructure without rebuilding your application.
Migration effort: Medium. LegacyLeaps handles steps 1 and some of step 4. The table migration and re-linking (steps 2-3) typically takes 1-3 days for a moderately complex database. Step 5 depends on application complexity.
Ongoing cost: SQL Server licensing. Access licensing is already included in Microsoft 365.
| Factor | Choose .accdb | Choose Hybrid | Choose Full SQL Server |
|---|---|---|---|
| Concurrent users | 1-15 | 10-50 | 50+ |
| Database size | Under 1GB | Under 10GB | Any size |
| Application complexity | High (preserve) | High (preserve) | Low (rebuild) |
| SQL Server already in use | No | Yes | Yes |
| Migration budget (developer hours) | 4-20h | 20-60h | 60-200h+ |
| Primary driver | Windows compatibility | Scalability + compatibility | Enterprise features / rebuilding |
| LegacyLeaps's role | Full migration | Step 1 (.mdb→.accdb) | Minimal |
The most common mistake is choosing the full SQL Server path for a database that's a perfect candidate for .accdb migration.
The reasoning usually goes: "We should do this right. SQL Server is the enterprise solution. Access is for small things." So the team spends 80 development hours rebuilding an Access application in .NET or Power Apps — an application that worked perfectly fine, just needed a format conversion to run on modern Windows.
The .accdb path isn't a compromise. For most Access databases — the ones serving departments, small teams, and internal business processes — it's exactly the right answer. It's faster, cheaper, and it preserves the institutional knowledge embedded in 15 years of VBA and form design.
The SQL Server path is right for the databases that have genuinely outgrown Access. Those exist, and for them, the migration investment is worth it. But they're the minority, not the majority.
Run LegacyLeaps's free scan. It shows you the database size, VBA complexity, form count, and table dependencies — the exact information you need to make the right migration decision.
Try the Free ScanPath 1 (.accdb migration): LegacyLeaps handles the full migration — format conversion, VBA 64-bit compatibility updates, linked table refresh, ActiveX audit, and data integrity verification.
Path 3 (Hybrid): LegacyLeaps handles the first step — .mdb to .accdb conversion with VBA updates. You then upsize tables to SQL Server using Access's Upsizing Wizard or SSMA, then re-link. LegacyLeaps's pre-migration scan helps you understand the full application complexity before you commit to the hybrid approach.
Path 2 (Full SQL Server): Use SSMA for the data migration. LegacyLeaps is less relevant here since you're rebuilding the application layer anyway.
Schedule a free consultation. We'll assess your database — VBA complexity, form count, table dependencies, and performance requirements — and recommend the right migration path for your organization.
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