Local Store

This guide outlines a robust workflow for mirroring emails from a remote IMAP server to a local store archive, and archiving old emails to local storage.

IMAP stands for Internet Message Access Protocol, a standard protocol that lets you access and manage your emails on a remote server from multiple devices, keeping everything synchronized (reading, deleting, organizing) across your phone, computer, and webmail.

The core principle is to maintain a local mirror of your remote mailbox using mbsync, perform the archival (moving files) on the local mirror, and then use mbsync again to propagate the local changes (the "deletions" from the mirrored folder) back to the remote server.

Prerequisites

isync Installed: You must have isync (which provides the mbsync command) installed on your system.

mbsync/isync
notmuch

bash

brew install isync

Create config file

Configured isyncrc: A working ~/.config/isyncrc file must be set up for the target email account. The configuration must include Expunge Both to ensure that deletions on the local mirror are synced to the remote server.

Create either file is acceptable:

~/.mbsyncrc (older style but acceptable)
~/.config/isyncrc I use this config file

Example isyncrc Channel configuration:

Channel twine
Far :twine-remote:
Near :twine-local:
Patterns *
Sync All
Expunge Both  # <-- This is critical for the workflow
Create Near
Remove Near
SyncState *

Making the directories

Create a folder as the local store for each email account.

bash

~/.maildir/twine
~/.maildir/soundfreaq
~/.maildir/biaget

下面我们以 twine 为例进行配置。

Directory Structure

~/.maildir/
├── twine/           # Active IMAP sync folder (mbsync manages this)
│   ├── INBOX/
│   ├── Sent/
│   ├── Drafts/
│   └── Trash/
├── 2025/            # Local archive for 2025 emails (YOU manage this)
│   ├── cur/
│   ├── new/
│   └── tmp/
└── 2026/            # Local archive for 2026+ emails (YOU manage this)
    ├── cur/
    ├── new/
    └── tmp/

Key Point: Only twine/ is synced with the remote IMAP server. Archives (2025/, 2026/) are local-only.

Why Archive?

Problem	Solution
IMAP storage quota filling up	Move old emails to local archives
Slow mailbox performance	Keep only recent emails synced
Need to retain old emails for reference	Local archives remain accessible in NeoMutt
mbsync syncs everything	Archives are excluded from sync

The Archiving Process

Step 1: Perform a Full Initial Sync

Before making any changes, ensure your local mail mirror is perfectly up-to-date with the remote server. This is a critical safety step.

Run mbsync for your account (replace twine with your channel name if different):

bash

mbsync twine

Wait for this command to complete successfully. Your local ~/.maildir/twine/ directory now mirrors the remote server.

Step 2: Create the Local Archive Folder

Create a new directory on your local machine to store the archived emails. It's important to create it in the Maildir format, which requires cur, new, and tmp subdirectories.

bash

# Create an archive folder for emails from 2025
mkdir -p ~/.maildir/2025/{cur,new,tmp}

Step 3: Move Emails Locally

Understanding Maildir Timestamps

Maildir filenames start with a Unix timestamp (seconds since 1970-01-01):

1769655740.80796_1.AX-Mac-mini,U=429:2,S
│
└─┬─┘
  │
  Timestamp = 1769655740 → Thu Jan 29, 2026 11:02:20 CST

Convert timestamps to dates:

bash

# Single timestamp
date -r 1769655740

# Preview all emails with dates in INBOX
for f in ~/.maildir/twine/INBOX/cur/*; do
    ts=$(basename "$f" | cut -d. -f1)
    echo "$ts → $(date -r "$ts" '+%Y-%m-%d')"
done | head -20

Common cutoff timestamps:

Archive Date	Cutoff Timestamp	Description
End of 2025	`1735689600`	Emails before Jan 1, 2026
End of Jan 2026	`1769938460`	Emails before Feb 1, 2026
End of Feb 2026	`1772530800`	Emails before Mar 1, 2026

Calculate your own:

bash

date -j -f "%Y-%m-%d %H:%M:%S" "2026-02-01 00:00:00" +%s

Method A: Manual Method using Yazi (File Manager)

If you prefer visual file browsing:

Open Yazi (or Finder) and navigate to ~/.maildir/twine/INBOX/cur/
Sort by name (filenames are timestamped, so oldest first)
Select emails from January 2026 and earlier
Move (not copy) selected files to ~/.maildir/2026/cur/
Repeat for twine/INBOX/new/ → 2026/new/ if any unread old emails exist

⚠️ Warning: Always move, never copy. Copying will cause duplicates and mbsync may re-upload them to the server.

Method B: Terminal Commands

Preview what will be moved:

bash

# Emails before Feb 1, 2026 (timestamp 1769938460)
CUTOFF=1769938460

echo "=== Emails to be archived ==="
count=0
for f in ~/.maildir/twine/INBOX/cur/*; do
    ts=$(basename "$f" | cut -d. -f1)
    if [ "$ts" -lt "$CUTOFF" ]; then
        echo "  $(date -r "$ts" '+%Y-%m-%d') : $(basename "$f" | head -c 50)..."
        count=$((count + 1))
    fi
done
echo "Total: $count emails"

Execute the move:

bash

CUTOFF=1769938460  # Adjust based on your needs

# Move from cur/
for f in ~/.maildir/twine/INBOX/cur/*; do
    ts=$(basename "$f" | cut -d. -f1)
    if [ "$ts" -lt "$CUTOFF" ]; then
        mv "$f" ~/.maildir/2026/cur/
    fi
done

# Move from new/ (if any unread old emails)
for f in ~/.maildir/twine/INBOX/new/*; do
    [ -f "$f" ] || continue
    ts=$(basename "$f" | cut -d. -f1)
    if [ "$ts" -lt "$CUTOFF" ]; then
        mv "$f" ~/.maildir/2026/new/
    fi
done

echo "Archive complete!"

Verify the move:

bash

# Count remaining in twine
echo "twine/INBOX/cur: $(ls -1 ~/.maildir/twine/INBOX/cur | wc -l)"
echo "twine/INBOX/new: $(ls -1 ~/.maildir/twine/INBOX/new | wc -l)"

# Count archived
echo "2026/cur:        $(ls -1 ~/.maildir/2026/cur | wc -l)"
echo "2026/new:        $(ls -1 ~/.maildir/2026/new | wc -l)"

Method C: Automation Script

Create a reusable archive script:

bash

#!/bin/bash
# ~/.local/bin/maildir-archive
# Usage: maildir-archive 2026-02-01

set -e

if [ -z "$1" ]; then
    echo "Usage: $0 <cutoff-date>"
    echo "Example: $0 2026-02-01"
    exit 1
fi

CUTOFF_DATE="$1"
CUTOFF_TS=$(date -j -f "%Y-%m-%d" "$CUTOFF_DATE" +%s)
ARCHIVE_DIR="$HOME/.maildir/2026"

echo "Archiving emails before $CUTOFF_DATE (timestamp < $CUTOFF_TS)"

# Create archive structure if needed
mkdir -p "$ARCHIVE_DIR"/{cur,new,tmp}

# Archive from INBOX
for folder in INBOX Sent Drafts; do
    src="$HOME/.maildir/twine/$folder"
    [ -d "$src/cur" ] || continue

    echo "Processing $folder/cur..."
    count=0
    for f in "$src/cur"/*; do
        [ -f "$f" ] || continue
        ts=$(basename "$f" | cut -d. -f1)
        if [ "$ts" -lt "$CUTOFF_TS" ]; then
            mv "$f" "$ARCHIVE_DIR/cur/"
            count=$((count + 1))
        fi
    done
    echo "  Moved $count emails"
done

echo "Done! Run 'mbsync twine' to sync changes to server."

Make it executable:

bash

chmod +x ~/.local/bin/maildir-archive

Usage:

bash

# Archive all emails before February 2026
maildir-archive 2026-02-01

# Archive all emails before March 2026
maildir-archive 2026-03-01

Step 4: Propagate Deletions to the Remote Server

This is the final and irreversible step. Run mbsync again.

bash

mbsync twine

mbsync will detect that hundreds of files are missing from your local Near mirror (~/.maildir/twine/INBOX). Because of the Expunge Both setting, it will interpret this as a command to delete those same emails from the Far remote server.

Once the command finishes, the old emails are now gone from the server and reside safely in your local archive.

Access the Archives in NeoMutt

Account Config with Local Archives

Update your maildir-twine config to add archives to the sidebar with visual labels:

bash

# Active folders (polled for new mail)
mailboxes -label "📥 INBOX"   -notify -poll "+INBOX"

# Standard folders (no poll, shown in sidebar)
mailboxes -label "📤 Sent"    -nonotify "+Sent" \
          -label "📝 Drafts"  -nonotify "+Drafts" \
          -label "🗑️ Trash"   -nonotify "+Trash"

# Archive folders (local only, no sync)
mailboxes -label "📁 2025"    -nonotify "~/.maildir/2025" \
          -label "📁 2026"    -nonotify "~/.maildir/2026"

Sidebar now shows:

│ 📥 INBOX   │  15
│ 📤 Sent    │   0
│ 📝 Drafts  │   3
│ 🗑️ Trash   │   0
│ 📁 2025    │ 450
│ 📁 2026    │ 120

Add these to your config for instant archive access:

bash

# Press '25' for 2025 archive, '26' for 2026 archive
bind index,pager 2 noop
macro index,pager 25 "<change-folder>~/.maildir/2025<enter>" "Go to 2025 archive"
macro index,pager 26 "<change-folder>~/.maildir/2026<enter>" "Go to 2026 archive"

Using the Archives in NeoMutt

Action	Key	Description
Toggle sidebar	`\` (backslash)	Show/hide folder list
Navigate folders	`Ctrl+Up/Down`	Move through sidebar
Open folder	`Enter`	View selected folder's emails
Quick archive	`25` / `26`	Jump to 2025/2026 directly
Change folder	`C`	Browse all folders
Return to INBOX	`q` (until back)	Navigate back to main inbox

Maintenance & Best Practices

Yearly Archive Rotation

At the start of each year, create a new archive:

bash

# January 2027: Create 2027 archive
mkdir -p ~/.maildir/2027/{cur,new,tmp}

# Add to maildir-twine config:
mailboxes -label "📁 2027" -nonotify "~/.maildir/2027"

Backup Your Archives

Archives are local-only, so backup is critical:

bash

# Time Machine (macOS) - automatic if ~/.maildir is included

# Or manual backup to external drive
rsync -av ~/.maildir/2025/ /Volumes/Backup/maildir-archives/2025/
rsync -av ~/.maildir/2026/ /Volumes/Backup/maildir-archives/2026/

Troubleshooting

Issue	Solution
Archives don't appear in sidebar	Check paths are absolute (`~/.maildir/2025` not `+2025`)
mbsync tries to sync archives	Ensure only `twine/` is in mbsync config
Emails reappear after mbsync	You copied instead of moved; delete originals
NeoMutt shows "unable to open mailbox"	Verify folder structure: `mkdir -p folder/{cur,new,tmp}`

Disk Space Monitoring

bash

# Check archive sizes
du -sh ~/.maildir/2025 ~/.maildir/2026 ~/.maildir/twine

# Find largest emails in archive
find ~/.maildir/2026/cur -type f -exec du -h {} + | sort -rh | head -20

Local Store

Prerequisites

Create config file

Making the directories

Directory Structure

Why Archive?

The Archiving Process

Step 1: Perform a Full Initial Sync

Step 2: Create the Local Archive Folder

Step 3: Move Emails Locally

Understanding Maildir Timestamps

Method A: Manual Method using Yazi (File Manager)

Method B: Terminal Commands

Method C: Automation Script

Step 4: Propagate Deletions to the Remote Server

Access the Archives in NeoMutt

Account Config with Local Archives

Quick Navigation Macros

Using the Archives in NeoMutt

Maintenance & Best Practices

Yearly Archive Rotation

Backup Your Archives

Troubleshooting

Disk Space Monitoring

Resources

Local Store ​

Prerequisites ​

Create config file ​

Making the directories ​

Directory Structure ​

Why Archive? ​

The Archiving Process ​

Step 1: Perform a Full Initial Sync ​

Step 2: Create the Local Archive Folder ​

Step 3: Move Emails Locally ​

Understanding Maildir Timestamps ​

Method A: Manual Method using Yazi (File Manager) ​

Method B: Terminal Commands ​

Method C: Automation Script ​

Step 4: Propagate Deletions to the Remote Server ​

Access the Archives in NeoMutt ​

Account Config with Local Archives ​

Quick Navigation Macros ​

Using the Archives in NeoMutt ​

Maintenance & Best Practices ​

Yearly Archive Rotation ​

Backup Your Archives ​

Troubleshooting ​

Disk Space Monitoring ​

Resources ​

Local Store

Prerequisites

Create config file

Making the directories

Directory Structure

Why Archive?

The Archiving Process

Step 1: Perform a Full Initial Sync

Step 2: Create the Local Archive Folder

Step 3: Move Emails Locally

Understanding Maildir Timestamps

Method A: Manual Method using Yazi (File Manager)

Method B: Terminal Commands

Method C: Automation Script

Step 4: Propagate Deletions to the Remote Server

Access the Archives in NeoMutt

Account Config with Local Archives

Quick Navigation Macros

Using the Archives in NeoMutt

Maintenance & Best Practices

Yearly Archive Rotation

Backup Your Archives

Troubleshooting

Disk Space Monitoring

Resources