“You don’t have permission to access this add-on”
If SheetDiff shows a message asking you to contact your organization administrator, nothing is broken and there is nothing to reinstall. Your workplace has not approved SheetDiff yet.
Google Workspace lets an employer decide which add-ons its staff may run. Many organizations approve add-ons one at a time, so anything new is blocked by default. The block happens before SheetDiff starts, which is why you see a Google message instead of the SheetDiff sidebar.
Option 1 — ask your IT administrator to approve it
Only your organization’s Google Workspace administrator can lift this. Send them the request below — approving an add-on takes them a minute or two.
Subject: Request to approve the SheetDiff add-on for Google Sheets Hi, I would like to use SheetDiff, a Google Sheets add-on that compares two tabs and reports the differences. When I try to run it I get a message saying I need organization approval. Could you allowlist it for my account or team? App name: SheetDiff - Compare and Reconcile Sheets Listing: https://workspace.google.com/marketplace/app/sheetdiff_compare_and_reconcile_sheets/544557039913 To approve it: Google Admin console -> Apps -> Google Workspace Marketplace apps -> Apps list -> Add app -> search for "SheetDiff" -> allowlist it. The add-on only reads the spreadsheet I run it on, and it does not transmit spreadsheet contents to any external server. Privacy policy and terms are linked from the Marketplace listing. Thanks,
Option 2 — use a personal Google account
A personal @gmail.com account has no administrator, so SheetDiff installs without approval. This is the fastest way to try it. Note that it only helps if you can copy the data you want to compare into a spreadsheet on that personal account — it will not give you access to spreadsheets that live in your work account.
Still stuck, or not sure which applies to you? Email sheetdiffapp@gmail.com and we will help you work out what your organization allows.