How To Configure Email

FolderSizes can send disk space analysis reports via email using SMTP. This guide covers setup for Gmail and Microsoft 365, the two most common cloud email providers.

GMAIL SETUP

Gmail requires an "app password" for SMTP access. Standard account passwords cannot be used.

Prerequisite: A Google account with 2-Step Verification enabled.

Steps:

1. Enable 2-Step Verification (if not already enabled):

  - Sign in at myaccount.google.com

  - Navigate to Security > 2-Step Verification

  - Follow the prompts to enable it

2. Generate an App Password:

  - Go to myaccount.google.com > Security > App passwords

    (or search for "App passwords" in your Google account settings)

  - Select "Other (Custom name)" and enter "FolderSizes"

  - Click Generate

  - Google will display a 16-character password — copy it immediately,

    as it cannot be viewed again

3. Configure FolderSizes email settings:

  - SMTP Host: smtp.gmail.com

  - SMTP Port: 587

  - Security: TLS (STARTTLS)

  - Authentication: Enabled

  - Username: your full Gmail address (e.g. user@gmail.com)

  - Password: the 16-character app password from step 2

  - From Address: your full Gmail address

MICROSOFT 365 / OUTLOOK SETUP

Microsoft 365 supports SMTP AUTH for sending email, but tenant administrators may need to enable it first.

Administrative Prerequisite: SMTP AUTH must be enabled for the sending mailbox. Microsoft disables it by default on many tenants. A tenant administrator can enable it using Exchange Online PowerShell:

 Set-CASMailbox -Identity "user@yourdomain.com" -SmtpClientAuthenticationDisabled $false

 Alternatively, the administrator can enable SMTP AUTH at the organization level via the Microsoft 365 admin center:

   - Go to admin.microsoft.com

   - Navigate to Settings > Org settings > Modern authentication

   - Ensure "Authenticated SMTP" is not blocked

Account Prerequisite: If Multi-Factor Authentication (MFA) is enabled on the account, an app password must be generated

Steps (with MFA enabled):

1. Generate an App Password:

  - Sign in at mysignins.microsoft.com/security-info

  - Click "Add sign-in method" and select "App password"

  - Name it "FolderSizes" and click Next

  - Copy the generated password

2. Configure FolderSizes email settings:

  - SMTP Host: smtp.office365.com

  - SMTP Port: 587

  - Security: TLS (STARTTLS)

  - Authentication: Enabled

  - Username: your full Microsoft 365 email address

  - Password: the app password from step 1 (or your account password

    if MFA is not enabled)

  - From Address: your full Microsoft 365 email address

Steps (without MFA): Use your regular account password in place of an app password. All other settings are the same as above.

GENERAL SMTP SETUP (OTHER PROVIDERS)

For other email providers or on-premises mail servers, use the SMTP connection details provided by your email administrator:

  - SMTP Host: your mail server hostname or IP address

  - SMTP Port: typically 587 (TLS/STARTTLS) or 465 (SSL)

  - Security: TLS or SSL as required by your server

  - Authentication: enable if your server requires it

  - Username/Password: as provided by your administrator

  - From Address: a valid sender address for your mail server

TROUBLESHOOTING

- "Authentication failed" errors: Verify that you are using an app password (not your regular account password) if MFA/2-Step Verification is enabled.

- "Connection timed out" errors: Confirm the SMTP host and port are correct. Ensure your firewall or network allows outbound connections on the configured port.

- Microsoft 365 "SMTP client submission disabled" errors: Ask your tenant administrator to enable SMTP AUTH for your mailbox using the PowerShell command listed above.

- Gmail "Less secure app" errors: Google no longer supports plain password authentication without 2-Step Verification. Enable 2-Step Verification and use an app password as described above.

- Enable SMTP session logging in the FolderSizes email settings to capture detailed protocol-level diagnostics for further analysis.