How can I compare two workspace exports before completing a migration?

Treat reconciliation as a set of checks, not a single count. Write down the intended scope—such as workspaces, record types, date range, and export options—and note when each export was created. Differences can reflect different scopes or ongoing changes, not just a migration problem.

Compare in layers:

1. Scope and totals by record type.
2. Record identity, using stable identifiers where available or a documented matching rule otherwise.
3. Selected key fields that exist in both exports.
4. Relationships exposed by the data, plus items that are missing, changed, or impossible to match.

For Microsoft Migration Manager cloud scenarios, reports can include item-level details, task summaries, source paths, destination locations, statuses, and errors. They can help investigate exceptions, but apply only to supported Microsoft 365 cloud migration scenarios and do not validate arbitrary workspace relationships. [S1]

Make an inventory of each export’s product, format, scope, filters, included record types, and known omissions. Check the products’ supported export and reporting options; similarly named files need not contain equivalent data.

For example, Slack export options depend on permissions, plan, and export type. Slack also documents a CSV channel audit listing channel details for migration planning or workspace management. [S2] Its exports can include channel and conversation data, while JSON exports may contain file links rather than the underlying files. [S3] So track expected linked files separately; matching message counts cannot establish that the files themselves are present.

A simple inventory is: Export | Scope | Included record types | Known omissions | Created at. If the available documentation does not establish whether an item or relationship is included, mark it “not verified.”

Use a sheet with one row per matched item or exception:

Record type | Source identifier | Destination identifier | Match status | Key fields checked | Relationship checked | Exception | Evidence / next action

Hypothetical example: compare a source channel with a possible destination match using your documented matching rule. Check fields present in both exports and note whether expected related records appear. If a Slack JSON export supplies a file link but not the file itself, record “linked file needs separate verification,” not “file present.” [S3]

For each record type, summarize matched, missing, destination-only, changed, and unmatched items. Keep the item-level list behind each total, and do not force uncertain matches to make the numbers align.

Call the comparison complete when the scope and matching rules are recorded, each planned check has a result, and every difference is explained, corrected and rechecked, or explicitly accepted by the responsible migration owner. That means the review is documented; it does not mean the exports prove every aspect of the destination is correct.

For unresolved items, record the evidence on both sides, why the exports cannot verify the item, who should review it, and the next action. Use supported reports or an approved workspace review when the exports cannot answer the question. Slack’s documentation describes its export formats and contents; it does not prescribe a general reconciliation method or establish completeness from matching counts. [S2] Mark relationships absent from both exports as unverified and ask the migration owner how to check them before sign-off.