“There was an error reading the rules from the server” in Outlook: how to fix it

What the error means

Your inbox rules are stored in your mailbox on the mail server, not just on your PC. When you open File > Manage Rules & Alerts, classic Outlook reads them from the server. If it can’t understand what it gets back, you see the full message: There was an error reading the rules from the server. The format of the server rules was not recognized.

Microsoft’s known-issue page, last updated in February 2026, says this can start after you change rules. Its example is a rule that uses the Display a Desktop Alert action: copying that rule and removing the alert action from the copy can trigger the error. Microsoft adds that this may not be the only cause, and it hasn’t announced a fix or a build that resolves it. Until it does, removing and recreating the rules is the supported route.

Which message do you see?

Several rules errors look alike but need different fixes:

Message	What to do
There was an error reading the rules from the server (format not recognized)	The known issue above. Export, delete all rules, recreate them (Fix 1 or Fix 2).
The rules on this computer do not match the rules on Microsoft Exchange	An older problem Microsoft fixed in 2020 builds. Update Office, then choose Server when asked which rules to keep, and turn deactivated rules back on.
One or more rules couldn’t be uploaded to Exchange server and have been deactivated	Usually the rules storage limit. See Fix 3.

For the middle row, Microsoft’s known-issue page says to update with File > Office Account > Update Options > Update Now. The prompt may appear one more time after updating.

Step 1: Export your rules first

Fixes 1 and 2 delete rules, and there’s no undo. If Outlook still lets you open the rules list, save a copy first:

1. In classic Outlook, go to File > Manage Rules & Alerts.
2. Select Options, then Export Rules.
3. Save the .rwz file somewhere you’ll find it, such as Documents.

If the rules window won’t open at all, write down what your important rules did (sender, folder, action) so you can rebuild them by hand. An exported file can also bring the broken rule back, so if the error returns after an import, recreate the rules manually instead.

Fix 1: Delete the rules in Outlook on the web

This is the gentler of Microsoft’s two workarounds because it only touches the one mailbox:

1. Close classic Outlook.
2. Sign in to Outlook on the web (outlook.office.com for work or school, outlook.com for personal accounts).
3. Open Settings > Mail > Rules.
4. Delete every rule, using the delete option next to each one.
5. Open classic Outlook again and check that Manage Rules & Alerts opens without the error.
6. Import your .rwz file from Options in the same window, or recreate the rules.

Recreating rules in Outlook on the web is a good habit here: those rules run on the server, so they work in classic Outlook, new Outlook and on your phone.

Fix 2: Clear rules with a startup switch

Outlook has three startup switches for rules. Close Outlook, press Win + R, type one of these and press Enter:

Switch	What Microsoft says it does
outlook.exe /cleanrules	Starts Outlook and deletes client-based and server-based rules.
outlook.exe /cleanserverrules	Starts Outlook and deletes server-based rules.
outlook.exe /cleanclientrules	Starts Outlook and deletes client-based rules (rules that run only on this computer).

/cleanrules is the one Microsoft gives as the workaround. Its warning matters: it removes rules for all accounts in the Outlook profile, not only the mailbox with the error. If you have several accounts in Outlook, export each account’s rules first, or use Fix 1 instead.

If Outlook won’t start normally at all, that’s a different problem; see how to reset Outlook to default settings.

Fix 3: Rules are full or deactivated

Rules share a fixed amount of space in your mailbox. Microsoft’s Exchange Online article says all inbox rules are limited to 256 KB in total, and that this limit can’t be increased in Exchange Online. When it’s full, Outlook warns that you can’t create or update rules, or deactivates rules it can’t upload.

To free space:

• Delete rules you no longer use.
• Combine similar rules, for example one rule that moves mail from several senders to the same folder.
• Shorten long rule names.
• Turn off on this computer only where you don’t need it.

On on-premises Exchange Server, older Microsoft guidance gives a 64 KB default that an admin can raise to 256 KB. That higher ceiling doesn’t exist in Microsoft 365, so the only real fix there is fewer or simpler rules.

New Outlook and rules

New Outlook manages rules in Settings > Mail > Rules rather than Manage Rules & Alerts. Microsoft’s rules guide says some rules made in classic Outlook can’t run in new Outlook because they’re client-side rules, and the answer is to recreate them. New Outlook also doesn’t support rules for Gmail, Yahoo or iCloud accounts. If you’re thinking of switching back, see how to get classic Outlook back.

For IT admins

• List a user’s rules, including hidden ones: Get-InboxRule -Mailbox [email protected] -IncludeHidden.
• Remove them all: Get-InboxRule -Mailbox [email protected] | Remove-InboxRule (try -WhatIf first).
• Check the quota: Get-Mailbox -Identity [email protected] | Format-List RulesQuota.

Microsoft’s Remove-InboxRule page warns that creating, changing or removing any inbox rule in Exchange PowerShell removes the client-side rules Outlook created, so warn the user before you run it. As a last resort, Microsoft has described deleting hidden rule messages (IPM.Rule.Version2.Message) from the inbox’s associated contents with MFCMAPI, in an older archived blog post. It’s a permanent delete, so export rules first and only use it if the steps above fail.

Fixes you can skip

Many guides suggest renaming Outlook.srs or running ScanPST. Neither is in Microsoft’s guidance for this error. The SRS file holds send and receive settings, and ScanPST repairs local data files, while this error is about rules stored on the server. They’re unlikely to help, and a new Outlook profile didn’t help in at least one report on Microsoft’s Q&A forum.

If rules seem to run but mail won’t go into folders, see can’t move emails to folders in Outlook. For faster ways to work with rules and folders, see our Outlook tips.

Related guides

• Can’t move emails to folders in Outlook: how to fix it
• How to reset Outlook to default settings (classic and new Outlook)
• Classic Outlook download: how to get it back on Windows 11 and 10
• Outlook Tips and Tricks: 12 Ways to Manage Email Faster in Outlook for Windows
• Outlook error 0x800CCC0E: cannot synchronize subscribed folders (Gmail and Yahoo)

Official sources

• Users get error There was an error reading the rules from the server (Microsoft Support)
• Increase or customize the space used by Inbox rules (Microsoft Learn)
• Use rules in new and classic Outlook for Windows (Microsoft Support)