MailConsolidator

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MailConsolidator is a Python application that consolidates email from multiple source accounts (POP3/IMAP) into a single destination IMAP mailbox.

Starting in January 2026, Google states that Gmail will no longer support fetching messages from third-party accounts into Gmail via POP using “Check mail from other accounts” in Gmail settings. MailConsolidator is intended as a practical alternative: it fetches mail from your source accounts and uploads it to the destination IMAP server (including Gmail), so you can continue managing messages in one place.

Table of Contents

• Overview

• Key Features

• Requirements

• Installation

  • Windows (Recommended)
  • From Source (Developers)

• Usage

  • GUI Mode
  • Startup Modes
  • Options
  • Daemon Management

• Gmail Notes

• Configuration

  • File Location
  • Schema
  • Field Reference

• Processing Behavior

• Troubleshooting

• Documentation

• Security Notes

• License

Why MailConsolidator

Google has announced that, starting in January 2026, Gmail will no longer support fetching messages from third-party accounts into Gmail via POP using the “Check mail from other accounts” feature. This change affects users who have relied on Gmail to periodically retrieve mail from external POP servers and manage all messages within a single Gmail inbox.

MailConsolidator is designed to fill this gap. Instead of relying on Gmail’s built-in POP fetching, it independently retrieves messages from source mail servers (POP3 or IMAP) and uploads them to a destination IMAP server, including Gmail. This approach preserves a centralized inbox workflow while avoiding dependency on deprecated Gmail functionality.

In short, MailConsolidator provides:

• Continuity for workflows impacted by Gmail’s POP deprecation
• Explicit control over mail retrieval, retention, and scheduling
• A provider-agnostic solution that works with any standard POP3/IMAP server

Overview

MailConsolidator retrieves messages from multiple mail servers and transfers them to a specified IMAP server, enabling centralized mail management. It supports both a GUI and a command-line interface, and it can run automatically on a schedule.

Key Features

• Multi-protocol sources: Fetch from POP3 and IMAP
• Unread-only IMAP fetching: Efficiently fetch only unread messages for IMAP sources
• Scheduled execution: Run consolidation at a configurable interval
• Real-time status: Monitor processing status in the GUI
• System tray integration (Windows): Run in the background from the Windows system tray
• Single-instance behavior: When already running, a new launch brings the existing GUI to the foreground (via IPC)
• Per-source retention policy: Choose whether to keep or delete messages on the source server
• SSL/TLS support: Secure connections
• Windows installer: Optional installer for easier setup

Requirements

• Python 3.7 or later
• PyYAML
• psutil
• cryptography
• pystray (Windows system tray)
• Pillow (image handling)
• certifi (CA bundle for SSL)

Installation

Windows (Recommended)

1. Download the installer

   • MailConsolidator-Setup-1.0.0.exe from GitHub Releases:

     • https://github.com/techstrom/MailConsolidator/releases/download/v1.0.0/MailConsolidator-Setup-1.0.0.exe

2. Run the installer

   • Double-click the installer and follow the wizard.

3. Launch

   • Start from the Start menu or desktop shortcut.

From Source (Developers)

1. Clone the repository:

git clone <repository-url>
cd MailConsolidator

2. Install dependencies:

pip install -r requirements.txt

3. Run:

python main.py

Usage

GUI Mode

Start the GUI:

python main.py

You may also run MailConsolidator.exe from the repository’s dist folder (if available).

Single-instance behavior: If the application is already running, a new launch will not start a second instance. Instead, it will bring the existing GUI window to the foreground and keep background tasks running.

GUI Workflow

1. Destination Settings

   • Enter destination IMAP server details
   • Click Save Settings

2. Source Settings

   • Add one or more source accounts
   • Provide protocol (POP3/IMAP), server information, and credentials
   • Configure Delete after move per account

3. Execution Panel

   • Run Now: Execute consolidation immediately

   • Start/Stop Scheduled Run: Toggle periodic execution (minutes)

     • Auto-save: Changing the interval and leaving the field automatically writes to the config file

   • Exit Application: Fully terminate MailConsolidator

   • Status Monitor: View processing status in real time

4. Window Close (×)

   • Choose one:

     • Exit Application (terminate)
     • Run in Background (hide window, stay in system tray)
     • Cancel

Startup Modes

Default Startup (Background)

Starts the GUI in the background and returns control to the shell immediately:

python main.py

On Windows, the system tray icon provides:

• Show/Hide Window
• Toggle Scheduled Run
• Exit

GUI Foreground Mode (Verbose)

Starts the GUI and prints detailed logs to the console:

python main.py -v

Daemon Mode (No GUI)

Runs in the background without opening the GUI:

python main.py -d

Options

• -d, --daemon: Run in daemon mode (no GUI)

• -k, --kill: Stop a running daemon process

• -c, --config: Path to the configuration file

  • Default (Windows): %APPDATA%\MailConsolidator\config.yaml
  • Default (Unix-like): ~/.config/MailConsolidator/config.yaml

• -v, --verbose: Print verbose logs (GUI mode)

• -l, --log-file: Write logs to the specified file

Examples:

# Default: GUI starts in the background
python main.py

# Write logs to a file
python main.py -l app.log

# GUI foreground with console logs
python main.py -v

# Daemon mode with log file
python main.py -d -l daemon.log

# Stop a running daemon
python main.py -k

Daemon Management

You can stop a background daemon using:

1. System tray menu (Windows GUI mode)

2. Exit Application button in the GUI

3. The -k option:

   python main.py -k

4. Terminate the process directly:

   • Windows: Task Manager
   • Unix-like: kill

The daemon state is tracked via a mailconsolidator.pid file in the system temporary directory.

Gmail Notes

POP-based fetching in Gmail

Google has announced that, starting January 2026, Gmail will no longer support fetching emails from third-party accounts into Gmail via POP using “Check mail from other accounts”.

Gmail App Password

If your Gmail account has 2-Step Verification enabled, use a Google App Password instead of your regular password.

Gmail IMAP Settings

Verify these settings:

• IMAP access: enabled (Gmail Settings → Forwarding and POP/IMAP)
• Host: imap.gmail.com
• Port: 993
• SSL/TLS: enabled

Configuration

File Location

The configuration file is saved automatically in a platform-appropriate location:

• Windows: %APPDATA%\MailConsolidator\config.yaml
• Unix-like: ~/.config/MailConsolidator/config.yaml

If an older config.yaml exists in the startup directory, it will be copied to the new location on first launch (the original file is not deleted).

You can override the path with -c:

python main.py -c "C:\custom\path\to\config.yaml"

Schema

interval: 3  # scheduled execution interval (minutes)

destination:
  host: imap.example.com
  port: 993
  user: [email protected]
  password: your_password_or_app_password
  ssl: true
  folder: INBOX

sources:
  - protocol: imap  # or pop3
    host: imap.gmail.com
    port: 993
    user: [email protected]
    password: your_gmail_app_password
    ssl: true
    folder: INBOX  # IMAP only
    delete_after_move: false  # true to delete after transfer

  - protocol: pop3
    host: pop.example.com
    port: 995
    user: [email protected]
    password: password
    ssl: true
    delete_after_move: true

Field Reference

destination

• host: IMAP server hostname
• port: Port (typically 993)
• user: Username (email address)
• password: Password (use an app password for Gmail)
• ssl: Use SSL/TLS (true recommended)
• folder: Destination folder (default: INBOX)

sources

• protocol: imap or pop3

• host: Mail server hostname

• port: POP3 (typically 995) / IMAP (typically 993)

• user: Username (email address)

• password: Password (app password for Gmail)

• ssl: Use SSL/TLS (true recommended)

• folder: Source folder (IMAP only; default: INBOX)

• delete_after_move: Whether to delete messages from the source after transfer

  • true: Delete (recommended for POP3)
  • false: Keep (recommended for IMAP; messages are marked as read)

Processing Behavior

IMAP + delete_after_move: false

1. Fetch unread messages only
2. Upload to the destination IMAP server
3. Mark as read on the source server
4. Next run will skip those messages

IMAP + delete_after_move: true

1. Fetch unread messages only
2. Upload to the destination IMAP server
3. Delete from the source server

POP3 Notes

POP3 does not have a read/unread concept. If delete_after_move: false, the same messages may be fetched repeatedly. For POP3 sources, delete_after_move: true is strongly recommended.

Troubleshooting

Authentication failures

Symptom: [AUTHENTICATIONFAILED] Invalid credentials

Actions:

1. For Gmail, confirm you are using an App Password (not your regular password)
2. Ensure the password contains no spaces
3. Confirm that 2-Step Verification is enabled

Duplicate messages

• IMAP: confirm that messages are marked as read when delete_after_move: false
• POP3: switch to delete_after_move: true

Connection issues

1. Verify host and port
2. Confirm SSL/TLS configuration (ssl: true for Gmail)
3. Check firewall rules
4. Confirm IMAP access is enabled

SSL error when running the EXE

Symptom: [Errno 2] No such file or directory: ... base_library.zip

Resolution: Recent versions address this by using certifi. Rebuild with:

pip install certifi
pyinstaller MailConsolidator.spec

Documentation

• Requirements Definition (REQUIREMENTS.md)
• Program Specification (SPECIFICATION.md)

Security Notes

• The configuration file (config.yaml) stores passwords in encrypted form; however, file system permissions still matter. Restrict access to your user account.
• For accounts with high message volume, the first run may take time.
• Mail servers may enforce connection-rate limits; aggressive polling can result in temporary blocking.

License

This project is released under the MIT License.