We already cleaned up or deleted old data. Is anything left?

Often some of it. Deleted mail, files and tickets stay restorable for days or weeks, Outlook keeps deleted mail until someone empties Deleted Items, and holds, backups and other people’s copies can keep more. Past a window with no hold, the vendor’s copy is gone.

How long can deleted data still be restored?

It depends on the system and on what was deleted. Without a hold or retention rule, as of October 2026:

System	What was deleted	How long it can come back	Who restores it
Microsoft 365 (Outlook)	Mail a user deleted	Until someone empties Deleted Items or an admin’s rule clears it; Microsoft’s default policy “doesn’t include a default tag to automatically delete content from the Deleted items folder”	The user, by moving it back
Microsoft 365 (Outlook)	Mail emptied from Deleted Items	14 days by default, up to 30 if an admin raised it; then “the item is removed from Exchange Online”	The user or an admin
Microsoft 365 (SharePoint, OneDrive)	Files	93 days across two recycle bins, then “permanently deleted”	The user or an admin
Google Workspace (Gmail)	Mail a user deleted	30 days in Trash, then “admins have an additional 25 days to restore messages”	The user, then an admin
Google Workspace (Drive)	Files	30 days in Trash; once a user empties Trash, an admin can recover items “within 25 days”	The user, then an admin
Slack	A message someone deleted	No undo: “Deleting a message is permanent”. A paid workspace set to keep all messages and save edits will “track message edits and deletions”	Nobody, in the app
Slack	Messages removed by a retention setting	None: “Data deleted according to your retention setting is permanent”	Nobody
Zendesk	Tickets	30 days in the Deleted tickets view, then “automatically permanently deleted”; a ticket archived before deletion “will not display in the deleted tickets view”	Admins, and agents given permission

Work through the shortest windows first. Slack offers no undo, mail emptied from Outlook’s Deleted Items can be gone in 14 days, and Zendesk’s deleted tickets in 30. Accounts deleted when people left run on their own clock, set out in Can we include former employees’ mailboxes?, and a canceled subscription on the vendor’s, set out in Our records are spread across old systems.

Which kind of cleanup was it?

The kind decides where to look:

• If people deleted items one by one, check the windows above, then the other people on each thread, whose copies a deletion does not touch. Are old company emails worth anything? lists the other places mail survives.
• If an admin set a retention or auto-delete rule, what it removed is usually gone. Slack says so, and Google’s Vault help says a badly set rule “might allow Google services to immediately and irreversibly purge data”. Ask whether a hold kept anyone’s data out of the rule’s reach.
• If accounts were deleted when people left, see former employees’ mailboxes.
• If a server, PC or backup drive was wiped or recycled, only copies made before then remain, and old systems lists the places to look.

Could a hold, backup or archive still have it?

Possibly. These are the places that can outlast a deletion:

• Holds. Putting a Microsoft 365 mailbox on Litigation Hold stops Exchange from purging its Recoverable Items folder (Microsoft). Google says Vault may reach deleted Gmail past the 25-day window if a retention rule or hold covered it (Google). Slack’s legal holds, on Enterprise plans, keep messages and files “regardless of retention settings or if members edit or delete any content”. A hold keeps what still existed when it was set, not what was purged before (Microsoft 365 page).
• A separate backup service. If your IT firm backs up Microsoft 365, Google Workspace, Slack or your accounting software with another product, those copies follow that product’s retention, not the vendor’s. Ask what it covers, from which date, and how far back it keeps.
• Local archives. Outlook archive files on staff PCs, which the email page explains.
• Earlier exports. A migration, an audit or a past dispute may have produced an export that someone kept.

If a hold was set for a lawsuit or an investigation, ask whoever set it before treating what it kept as licensable; Can we include former employees’ mailboxes? explains why.

Should we restore it just because we can?

Not before asking why it was deleted. Three reasons to pause:

• Pending deletion requests. For companies California’s privacy law covers, its regulations let a business that holds personal information “on archived or backup systems” delay a consumer’s request to delete “until the archived or backup system relating to that data is restored to an active system or is next accessed or used for a sale, disclosure, or commercial purpose” (11 CCR §7022(d)). The regulation ties those delayed requests to that restore or use. Is it legal to sell company emails and records? covers which companies the law reaches; ask counsel how the rule applies to yours.
• Promises to delete. A client contract may require you to return or destroy its data when the work ends, and the IT managed services page lists the clause to look for. Data deleted to keep that promise stays deleted.
• Cost before interest. Restoring an old backup or reading a retired drive takes paid hours. Find out whether a provider wants those years before paying for it.

What is gone for good?

Whatever passed its window with no hold, backup or other copy, and the vendors say so. Google says purged Gmail “can’t be restored by an admin or by Google”, and that Drive items past their window are purged “from its systems and they can’t be recovered”. Zendesk says “there is no way to recover the permanently deleted ticket”. Exchange removes purged mail, SharePoint deletes files permanently after 93 days, and Slack calls both kinds of deletion permanent, as the table shows.

Does a gap make our records worthless?

No. It shortens what a buyer can price. Providers count years of history, and two put the question in terms of what was kept. Corpus puts “Archives retained rather than purged” on its qualifying checklist, and Avelence’s methodology says to “Use the period actually available in the relevant records, rather than company age.” (both as of October 2026). What remains is what you license, so write down the years each system holds, and where the gaps are and why. A gap shows in any sample counted by month, and Does my company’s data qualify? explains why colleagues’ mailboxes and your other systems often still cover years that one person’s deletion removed.

What do I do next?

1. Stop further cleanup. No more purges, account deletions or new deletion rules while you decide, and ask why any existing rule was set before changing it.
2. Work through the open windows, shortest first: emptied Outlook mail, then Zendesk tickets, then Gmail and Drive, then SharePoint files.
3. Ask your IT firm in writing about holds, backup services, old exports and archive files, and what each covers.
4. Check before restoring anything from a backup: deletion requests, client contracts and holds.
5. Record the result in your data inventory: what each system holds now, and the gaps with their causes.
6. Apply with that inventory, so providers price the years you actually have.