What it works with
Module: Local PowerShell
Context: Windows PowerShell 5.1 or PowerShell 7 · local CSV comparison
Compatibility: Pure local PowerShell; Windows PowerShell 5.1 and PowerShell 7 are supported.
POWERSHELL / MIGRATION
ProAdvancedRead-onlyLow
Compare pre- and post-migration Microsoft 365 inventory exports
Compares normalized pre- and post-migration CSV inventories locally and reports matched, missing, added and changed records without connecting to either tenant or a migration vendor.
Pro generation after license validation · Review before running · No tenant access by Opselith
What this PowerShell script does
Compares normalized pre- and post-migration CSV inventories locally and reports matched, missing, added and changed records without connecting to either tenant or a migration vendor.
Requirements
- Pre-migration CSV path - Source/pre-migration inventory CSV.
- Post-migration CSV path - Destination/post-migration inventory CSV.
- Dataset type - Selects sensible auto-key and comparison behavior.
- Match key - Use auto unless your two exports intentionally share a different stable key.
- Optional key mapping CSV - Optional CSV with SourceKey and DestinationKey for renamed identities or URLs.
- Comparison CSV path - Use a new absolute Windows CSV path.
Environment
- Module: Local PowerShell
- Runtime: 5.1 / 7
- Permissions: None. Comparison uses existing local CSV exports only.
- Risk: Low
Review before you runUse exports that represent the same workload and review the chosen match key. Supply SourceKey/DestinationKey mappings when identifiers intentionally changed.
OPS / WORKSPACE
Ready to generate
Configure Compare pre- and post-migration Microsoft 365 inventory exports in the Builder, review the generated PowerShell and run it in your own environment.
When to use this template
Use this after a migration wave to compare normalized source and destination exports with a stable key or an explicit source-to-destination key map.
Important limitations
- Comparison quality depends on the columns present in both CSVs. Fields absent from one side cannot be compared.
- Object IDs often change in tenant-to-tenant migration; use SMTP/UPN/URL/GroupId or an explicit mapping when appropriate.
- The script reports observed differences; it does not declare an entire migration successful or failed.
Generate the script
- Open this template in the PowerShell Builder.
- Enter the required values and review the documented permissions and output.
- Generate the script, inspect it, then run it in your own PowerShell environment.
OPS / SCRIPT DETAILS
Script details
Compares normalized pre- and post-migration CSV inventories locally and reports matched, missing, added and changed records without connecting to either tenant or a migration vendor. Review these details before generating or running the script.
Permissions and impact
Permissions: None. Comparison uses existing local CSV exports only.
Risk: Low
Execution impact: Read-only. Reads administrative data and does not intentionally change the target environment.
Parameters
- Pre-migration CSV path - Source/pre-migration inventory CSV.
- Post-migration CSV path - Destination/post-migration inventory CSV.
- Dataset type - Selects sensible auto-key and comparison behavior.
- Match key - Use auto unless your two exports intentionally share a different stable key.
- Optional key mapping CSV - Optional CSV with SourceKey and DestinationKey for renamed identities or URLs.
- Comparison CSV path - Use a new absolute Windows CSV path.
Output
Output: CSV with DatasetType, SourceKey, DestinationKey, Status, Column, SourceValue, DestinationValue and Warning.
This template is part of the Pro library. The full Pro script is generated by Opselith after server-side license validation; only the configuration values needed by this template are sent for generation. No tenant connection is required. When you generate a Pro script, only the configuration values needed for that template are sent to Opselith after license validation.
Example use
Compares normalized pre- and post-migration CSV inventories locally and reports matched, missing, added and changed records without connecting to either tenant or a migration vendor.
Enter the required values in the Builder, review the generated script and confirm the output before running it.
Before you run: Use exports that represent the same workload and review the chosen match key. Supply SourceKey/DestinationKey mappings when identifiers intentionally changed.
Opselith quality checks
- Included in the current Opselith PowerShell quality suite
- Local-only comparison
- Duplicate keys rejected
- Optional source-to-destination key mapping
- No giant nested JSON in CSV
- Formula-injection protection
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