Access Database Running Slow?
7 Performance Killers (and How to Fix Them)

When Speed Matters

It's 9am Monday morning. You open your Access database to pull the weekly sales report, and… nothing happens. The screen freezes. The mouse cursor shows that spinning wheel. Two minutes later, the database finally opens... But only to freeze again when you try to run a query!

This isn't just annoying, it's costing your business money every single day. Staff waste hours waiting for databases to respond. Reports that should take 30 seconds now take 10 minutes. Some businesses assume "Access is just slow" but that's rarely true.

Most Access slowness comes from 3-4 fixable mistakes. Many of these fixes take 5-10 minutes to implement. You don't always need to migrate to SQL Server or rebuild from scratch. This guide covers the 7 most common performance killers and shows you how to fix them.

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Understanding Why Access Gets Slow

Access databases aren't inherently slow, they're mostly abused and misused! The file-based architecture means different rules apply compared to SQL Server. Network placement, design choices, and data volume all matter. Most "slow Access" complaints trace back to the same 7 culprits.

Warning Signs Your Database Is in Trouble

• Forms take 10+ seconds to open
• Queries that used to run instantly now take minutes
• The database frequently "freezes" or shows "Not Responding"
• File size has grown past 500MB
• Multiple users report slowness at the same time
• Compact and Repair takes longer each time
• Reports fail to complete or show #Error messages

The 7 Performance Killers

Performance Killer #1: The Database Lives on a Network Share

Why it's deadly... Access wasn't designed for file sharing across networks. Every query loads entire tables across the network. Record-locking creates constant file access conflicts. WiFi connections make this exponentially worse.

The symptoms...

• Slowness increases with more users
• Performance is worse for remote/WiFi users
• Random "database is in an inconsistent state" errors

• Quick fix - Move database to local drive for single-user access
• Proper fix - Split the database (front-end/back-end architecture)
• Best fix - Migrate backend to SQL Server or Azure SQL

Implementation steps...

1. Create a backup of your current database
2. Use Database Tools → Access Database → Database Splitter
3. Place the backend on the server
4. Distribute front-end copies to each user's local machine

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Performance Killer #2: Missing or Broken Indexes

Why it's deadly... Access scans entire tables without indexes. A 50,000-row table without indexes can take 30+ seconds to query. Broken indexes after corruption act as if they don't exist.

The symptoms...

• Queries slow down as data grows
• Sorting and filtering take forever
• Forms with combo boxes lag when opening

How to identify...

Open any table → Design View → Click "Indexes" button. Look for:

• Primary keys without indexes
• Foreign key fields without indexes
• Frequently searched fields without indexes

The fix...

1. Open table in Design View
2. Select the field used in relationships (e.g., CustomerID)
3. In Field Properties → Indexed → Select "Yes (Duplicates OK)"
4. Save the table

Rule of thumb... Index fields you search/sort by, not fields you just display

Performance Killer #3: Inefficient Queries and VBA Code

Why it's deadly... Recordsets opened in wrong order (dynaset vs snapshot). Queries pulling entire tables when only 10 rows needed. VBA loops doing row-by-row updates instead of UPDATE queries. Queries with calculated fields in WHERE clauses.

The symptoms...

• Reports run slower as data grows
• Forms freeze when loading combo boxes
• Action queries take minutes to complete

Common query mistakes:

❌Please stop doing this...

Why is this bad? Calculates Year() for every row (can't use indexes)

✅Try this instead...

Whats the difference? Uses indexes, much faster

❌Another problematic VBA example...

✅Try this instead...

The fix...

• Review slow queries using Query Analyzer
• Replace row-by-row VBA loops with SQL UPDATE statements
• Use appropriate recordset types (snapshot for read-only)
• Avoid SELECT * when you only need specific fields

Performance Killer #4: Bloated Database File

Why it's deadly... Deleted records don't free up space. Temporary objects accumulate. Database fragments like a hard drive. Slows down everything, not just specific operations.

The symptoms...

• File size is 1GB+ but data seems smaller
• Compact and Repair reduces file size by 30%+
• General sluggishness across all operations

How to check...

1. Check current file size (Right-click file → Properties)
2. Run Compact and Repair
3. Check file size again
4. If it shrunk by >20%, you had bloat

And now the fix...

File → Info → Compact & Repair Database

Prevention...

1. Set up automatic compact on close: File → Options → Current Database → Compact on Close ✓
2. Schedule regular manual compacts (weekly/monthly)
3. Archive old data regularly...
   • Export records older than 2-3 years
   • Keep in separate archive database

For severe bloat...

1. Create new blank database
2. Import all objects from old database
3. This rebuilds everything from scratch

Performance Killer #5: Large Memo/Long Text Fields

Why it's deadly... Access loads entire memo fields even when displaying just 50 characters. Images and attachments stored in tables bloat file size. OLE Object fields are particularly terrible for performance.

The symptoms...

• Forms with memo fields load slowly
• Database file is huge compared to visible data
• Scrolling through records is choppy

The fix...

For images/documents:

• ❌ Don't: Store in Attachment or OLE Object fields
• ✅ Do: Store files in network folder, save file paths in Access

Example implementation...

Instead of: [Image] (Attachment field)

Use: [ImagePath] (Short Text field) = "\\server\images\photo123.jpg"

In forms, use Image Control: Me.ImageControl.Picture = Me.ImagePath

For long text that must be in database...

• Split into separate table loaded on-demand
• Create a "Details" table linked by ID
• Load only when user clicks "View Details" button

Performance Killer #6: Too Many Open Forms and Objects

Why it's deadly... Each open form consumes memory. Subforms multiply the problem. Hidden forms still use resources. Access's memory management is poor compared to modern apps.

The symptoms...

• Database gets slower the longer it's open
• Performance improves after closing and reopening
• "Out of memory" errors on computers with plenty of RAM

The fix...

In form design:

For popup forms:

For subforms:

• Limit subforms on main forms to 2-3 maximum
• Use tab controls to separate subforms (only loads active tab)
• Consider "Details" buttons instead of automatic subforms

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Performance Killer #7: Antivirus and Windows Search Indexing

Why it's deadly... Antivirus scans every read/write operation. Windows Search constantly indexes the .accdb file. OneDrive and Dropbox sync interfere with file locking. These issues compound with network-shared databases.

"Just like the slightest presence of gas caused the canary to die, the slightest presence of network problems and packet loss can kill your Access applications. Make sure you're not using the cheap built-in NICs that come with some PCs."

- KZ Software

The symptoms...

• Random pauses that don't correlate with user actions
• Worse performance during backup hours
• Inconsistent slowness (fast sometimes, slow others)

The fix...

Add to antivirus exclusions:

• The database file: C:\Databases\*.accdb
• The database folder: C:\Databases\
• Access executable: C:\Program Files\Microsoft Office\root\Office16\MSACCESS.EXE

Windows Search:

1. Control Panel → Indexing Options
2. Modify → Uncheck database locations
3. Advanced → File Types → Remove .accdb

OneDrive/Dropbox:

• ⚠️ Never run Access databases from sync folders
• Move database outside OneDrive/Dropbox folders
• See related article: Why Dropbox + Access Don't Mix

When Fixes Aren't Enough...

Signs You've Outgrown Access

• Database regularly approaches 2GB limit
• 10+ concurrent users need access
• Performance fixes only help temporarily
• Data volume growing rapidly

Better Long-Term Solutions

1. SQL Server backend (keep Access front-end)

• Handles larger data volumes
• Better multi-user support
• Maintains familiar interface
• Learn about SQL Server migration

2. Azure SQL Database (cloud-based)

• Remote access without VPN
• Automatic backups
• Scales with business growth
• Explore cloud strategy options

3. Power Apps + Dataverse (full modernization)

• Mobile-friendly interface
• Modern cloud platform
• Discover hybrid Access solutions

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Immediate Action Plan

What to Do Right Now (Next 30 Minutes)

Priority 1 fixes (do today)!

1. Run Compact and Repair
2. Check if database is on network share
3. Add antivirus exclusions
4. Check primary key indexes exist

Priority 2 fixes (this week)..

1. Split database if multi-user
2. Review and add foreign key indexes
3. Remove/archive old data
4. Replace memo fields with file path approach

Priority 3 fixes (this month)....

1. Audit and optimise slowest queries
2. Implement proper form closing procedures
3. Consider SQL Server migration if at 1.5GB+

Monitoring Performance Going Forward

Set calendar reminders...

• Weekly - Compact and Repair
• Monthly - Check file size growth
• Quarterly - Review query performance
• Annually - Evaluate if Access still meets needs

Conclusion

Key Takeaways

• Most Access slowness is fixable without expensive migrations
• The 7 performance killers account for 90%+ of speed issues
• Quick wins (indexes, compact, antivirus) take minutes
• Structural issues (network location, split database) take hours
• Know when to move beyond Access entirely

The Real Cost of Ignoring Performance

• Staff productivity loss: 10-30 minutes per day per user
• Business decision delays from slow reporting
• Risk of corruption from bloated, stressed databases
• Eventually hitting the 2GB wall

When to Call for Help

DIY fixes work for...

• Single-user or small team databases
• File sizes under 500MB
• Basic queries and forms

Professional help needed for:

• Business-critical databases (can't afford downtime)
• Complex VBA and query optimisation
• Migration to SQL Server or cloud
• Database recovery from corruption

About the Author

Scott founded Office Experts Group in 2000 and has since established himself as one of Australia's foremost authorities on Microsoft technologies. With decades of experience in design, programming, and consulting, he continues to help businesses unlock the full potential of Microsoft solutions.