MacReset Mail & Calendar Tool · macOS only

MacReset Mail & Calendar Tool — repair broken Mail and Calendar on Mac without deleting accounts.

MacReset Mail & Calendar Tool is a free signed macOS .pkg that repairs Apple Mail and Calendar by safely backing up and rebuilding corrupted local indexes and cache files. Missing emails, stuck sync, blank calendars, or Mail crashing on launch — run the tool, both apps rebuild clean, accounts and cloud data untouched.

This tool is non-destructive. Mail accounts, Calendar accounts and cloud data remain intact. Only local caches and indexes are rebuilt.
View All Reset Tools

macOS only · safe rebuild · automatic backup created

Need to reset printers instead? MacReset Printer Tool →

What this reset targets

  • ~/Library/Mail/V*/MailData (Envelope Index files)
  • ~/Library/Containers/com.apple.mail/.../Caches
  • ~/Library/Calendars (Calendar Cache)
  • ~/Library/Containers/com.apple.iCal/.../Caches

Run → backup created → corrupted databases removed → apps rebuild clean.

What this Mail & Calendar reset actually does

This tool surgically repairs local database corruption without deleting any real user data.

  • Gracefully quits Mail and Calendar
  • Backs up all index and cache files before touching anything
  • Deletes corrupted Mail envelope indexes
  • Clears broken Mail cache files
  • Clears Calendar cache & metadata files
  • Forces both apps to rebuild fresh databases on next launch

What it does not do

  • Does not delete Mail accounts
  • Does not remove Calendar accounts
  • Does not remove cloud-stored mail or events
  • Does not affect other macOS users
On large mailboxes, the first launch after reset can take several minutes while indexes rebuild. This is expected behaviour.

Mail & Calendar problems this fixes

These issues are almost always caused by corrupt local cache or index files.

Mail not syncing

New messages never arrive or appear hours late.

  • Exchange
  • Microsoft 365
  • iCloud

Missing or empty mailboxes

Folders show as empty even though webmail is correct.

  • Index corruption
  • Upgrade leftovers
  • Profile migrations

Calendar events vanish

Events disappear, duplicate, or refuse to sync.

  • iCloud desync
  • Exchange rebuild loops
  • Cache poisoning

Mail crashes or hangs

Mail freezes at launch or constantly re-indexes.

  • Broken cache database
  • Spotlight handoff failures
  • Large attachments index issues

How the reset works

This follows a safe backup → destroy → rebuild workflow.

1

Mail & Calendar shut down

Both apps are closed cleanly to avoid locked database files.

2

Automatic backups created

All affected cache and index files are copied to Documents/MacReset Backups.

3

Corrupt databases removed

Only local cache and envelope files are deleted.

4

Apps rebuild cleanly

Mail and Calendar regenerate fresh databases on next launch.

Your real mail and calendar data remains safely stored in iCloud, Exchange or your mail provider.

Manual repair (for masochists)

These are the same core steps performed manually.

1. Quit Mail & Calendar

Force close both apps.

2. Delete Mail Envelope Index

~/Library/Mail/V*/MailData/Envelope Index*

3. Clear Caches

Remove both Mail and Calendar cache folders.

4. Reopen & wait

Mail and Calendar re-index and resync.

Manual repairs frequently miss hidden container cache paths. The automated reset avoids partial failure states.