Legacy File Migration Checklist

Everything to do before, during, and after migrating .xls and .mdb files

Before You Migrate

Step 1: Inventory Your Files

• Run a directory scan for all .xls, .xlsb, .xlsm, .mdb files on your system or network
• Note the file size, last modified date, and owner for each file
• Flag files not opened in 12+ months as "low priority / archive"
• Flag files opened within the last 90 days as "active / migrate first"

Step 2: Audit for Macros and Code

• Open each .xls file and press Alt+F11 — check for VBA modules, class modules, or UserForms
• If macros exist: file must be saved as .xlsm (not .xlsx) to preserve them
• Note any Declare Function or Declare Sub statements — these need PtrSafe updates for 64-bit Office
• For .mdb files: open VBA editor and document any module names and API declarations

Step 3: Check for ActiveX Controls

• Review each Excel sheet for embedded controls (combo boxes, buttons, calendar pickers)
• Review each Access form for ActiveX dependencies
• OCX/DLL-based controls may require re-registration after migration
• Note any custom ActiveX controls from third parties — check if 64-bit versions exist

Step 4: Document Linked Files and External References

• Check for Excel external references (Data > Edit Links)
• Check for Access linked tables (External Data > Linked Table Manager)
• Map which files depend on which — convert dependencies first
• Note any ODBC connections or external database links

Step 5: Back Up Everything

• Copy all original files to a backup location before converting anything
• Confirm backup is complete and files open correctly from the backup location
• Note the backup path and date — keep backups for 90 days after migration

During Migration

Excel Files (.xls → .xlsm or .xlsx)

• If file has macros: Save As > Excel Macro-Enabled Workbook (*.xlsm)
• If file has NO macros: Save As > Excel Workbook (*.xlsx)
• NEVER save a macro-enabled .xls as .xlsx — macros will be permanently deleted
• Use a new filename — do not overwrite the original
• Fix all Declare Function/Declare Sub statements by adding PtrSafe keyword
• Update pointer-sized types from Long to LongPtr for API declarations

Access Databases (.mdb → .accdb)

• Open in Access 2007/2010/2013: Database Tools > Access Database
• Save with a new name — do not overwrite the original .mdb
• Check for reserved word conflicts in table/field names (Name, Date, Status, Text)
• Bracket reserved words in all SQL queries: [Name], [Date], etc.
• Fix any Declare statements in VBA (PtrSafe, as above)
• Run Compact and Repair on the new .accdb after conversion

After Migration — Validation

Excel Validation

• Open both old .xls and new .xlsm/.xlsx side by side
• Verify row and column counts match on every sheet
• Spot-check 10–15 complex formulas — confirm matching output
• Check for new errors: #REF!, #NAME?, #VALUE!, #N/A that weren't there before
• Press Alt+F11 — confirm all VBA modules, forms, and class modules are present
• Run each macro and confirm it executes without errors
• Test all form controls (buttons, dropdowns, checkboxes)
• Verify conditional formatting rules apply correctly
• Test all chart and pivot table refresh functions
• Confirm named ranges resolve correctly

Access Validation

• Open and test each form — verify all controls load and respond
• Test each query — verify results match the original .mdb output
• Run all reports — verify data populates correctly
• Test all VBA macros and event handlers
• Relink all linked tables (External Data > Linked Table Manager)
• Verify data row counts match between old .mdb and new .accdb
• Test multi-user access if applicable (open from two workstations simultaneously)
• Confirm security settings (Trusted Location, or re-sign the database)