How should email marketers handle Gmail addresses with overquota inboxes?
Michael Ko
Co-founder & CEO, Suped
Published 12 Aug 2025
Updated 19 Aug 2025
7 min read
Email marketers often face challenges with deliverability, and one common issue is encountering Gmail addresses with overquota inboxes. This means the recipient's Gmail storage is full, preventing them from receiving new emails. While it might seem like a straightforward temporary bounce, the implications for your email marketing strategy and sender reputation can be significant.
Google provides a generous amount of free storage (15 GB across Gmail, Google Drive, and Google Photos), so an inbox being consistently over quota often indicates that the user is not actively managing their email or has abandoned the account. Understanding this distinction is crucial for effective list management.
Mailbox full bounces are generally classified as soft bounces, meaning they are temporary delivery failures. However, if these bounces persist over time, they can signal a deeper problem than just a full inbox. My goal here is to outline how to identify and manage these situations to protect your deliverability and maintain a healthy sender reputation.
Properly handling these overquota addresses isn't just about reducing bounce rates, it's about ensuring your emails reach engaged subscribers and optimizing your overall email program. Ignoring these signals can lead to larger deliverability issues down the line, including being placed on a blacklist or blocklist.
Understanding overquota bounces
When an email marketer sends a message to a Gmail address that's over quota, they typically receive a 452 4.2.2 bounce code. This response indicates a temporary failure because the recipient's mailbox has exceeded its storage limit. While a temporary issue, consistent overquota bounces point towards an inactive or unmonitored mailbox.
It's important to remember that Google's storage is shared across various services like Gmail and Google Drive. If a user is over their limit, it's because their total Google account storage is full, not just their email inbox. You can learn more about how Google storage works on their official support page. Your mail server or email service provider (ESP) will typically retry sending the email for a certain period, but this retry policy needs to be carefully managed.
While some mail servers use a less aggressive retry policy, such as after 1, 3, 6, 12 hours, continuously trying to deliver to a persistently full mailbox can be detrimental. The primary concern is not just the failed delivery, but the potential negative impact on your sender reputation, as mailbox providers interpret repeated bounces as a sign of poor list hygiene. For additional information on handling such emails, ServerFault discusses bulk email strategies for over quota / mailbox full undeliverable emails.
Understanding the 452 4.2.2 error
This specific bounce code from Gmail indicates that the recipient's mailbox is temporarily unavailable due to being over quota. It's a soft bounce, meaning the issue is usually temporary and could resolve itself if the user clears space. However, consistent occurrences often suggest account inactivity rather than a transient problem.
Repeatedly sending emails to overquota mailboxes, even if they're soft bounces, can negatively impact your sender reputation. Mailbox providers (like Gmail) monitor bounce rates closely. A high rate of even soft bounces suggests that your list contains a significant number of inactive or unengaged contacts, which can trigger spam filters and result in your emails landing in the spam folder for other recipients.
Beyond reputation, continuous sending to these addresses wastes your sending resources and can inflate your active subscriber count, leading to inaccurate campaign performance metrics. While Gmail does not directly block email senders for overquota bounces, a consistently high volume can contribute to a poor sender score, making it harder to reach the inbox for all your campaigns.
Initially, an overquota bounce appears as a temporary issue. Your ESP or mail server will likely retry sending the email a few times, hoping the recipient clears space. This short-term retry mechanism is standard, but prolonged attempts can become problematic. Continuing to send without a strategy will inflate your bounce rate.
Long-term impact
Over time, consistent overquota bounces signal to mailbox providers that you are sending to unengaged or abandoned accounts. This degrades your sender reputation, making it more likely that your legitimate emails will be sent to the spam folder, even for recipients with active inboxes. It can also lead to blocklisting.
Strategies for handling overquota Gmail addresses
The key to handling overquota Gmail addresses is to implement a robust bounce management strategy. While it's tempting to keep retrying, research indicates that about a third of mailbox full bounces eventually open another email within a year, and roughly 20% do so within 30 days. This means some of these addresses are indeed still active, or become active again.
Therefore, the best approach is to suppress these addresses after a certain number of consecutive bounces over a defined period, such as 3-5 bounces over 3-4 weeks, rather than immediately removing them. This gives the recipient time to clear their inbox without unduly penalizing your sender reputation. For more on bounce analysis, MessageGears provides research on what bounces mean for super senders.
Beyond suppression, focus on proactive list hygiene. Regularly cleaning your list by removing inactive subscribers is critical. This not only improves your deliverability but also ensures your engagement metrics are accurate, allowing you to focus on your most responsive audience. Managing inactive email subscribers can significantly improve Gmail deliverability and help you rebuild sender reputation. It's also important to understand how to handle permanent bounce errors from full or inactive mailboxes.
Initial soft bounce: When the first overquota bounce occurs, most ESPs will automatically retry sending the email.
Monitoring consecutive bounces: Track the number of consecutive bounces from the same address. A common threshold is 3-5 bounces.
Time-based suppression: If an address continues to bounce over a period of 3-4 weeks without a successful delivery, it's a strong indicator for suppression.
Temporary suppression: Instead of a hard removal, consider a temporary suppression that allows for re-engagement attempts after a period if you believe the user might still be interested.
Example logic for handling overquota bouncesjavascript
if (bounce_type == 'soft' and bounce_reason == 'over_quota') {
increment_overquota_count(recipient_email);
if (get_overquota_count(recipient_email) >= 3 and time_since_last_success(recipient_email) >= '3 weeks') {
suppress_recipient(recipient_email);
log_suppression_reason(recipient_email, 'persistent_overquota');
} else {
retry_send_later(recipient_email, 'gradual');
}
}
Remove from active list, consider re-engagement campaign
Ensures list quality, reduces potential blocklist risk
Maintaining a healthy email list
Effectively managing Gmail addresses with overquota inboxes is a critical aspect of maintaining strong email deliverability. It requires a nuanced approach that balances patience with proactive list management.
By understanding the nature of these soft bounces, monitoring consecutive failures, and implementing a strategic suppression policy, marketers can minimize negative impacts on sender reputation and maximize the effectiveness of their campaigns. Prioritizing list hygiene and engaging with active subscribers will always yield the best results.
Ultimately, a clean, engaged email list is your most valuable asset. While it's important not to prematurely remove potentially active recipients, the long-term health of your email program depends on a vigilant approach to bounce management and list quality.
Views from the trenches
Best practices
Implement a clear bounce management policy: Suppress Gmail addresses after 3-5 consecutive overquota bounces over several weeks.
Segment your list: Create segments for recipients who consistently bounce and consider re-engagement campaigns for them separately.
Regularly clean your email list: Remove subscribers who show no engagement and consistently generate soft bounces.
Common pitfalls
Aggressive suppression: Immediately removing recipients after one or two overquota bounces might discard potentially engaged subscribers.
Ignoring soft bounces: Continuing to send to persistently overquota inboxes can negatively impact your sender reputation and inflate bounce rates.
Not monitoring Gmail Postmaster Tools: Failing to track bounce rates and reputation metrics for your Gmail sends.
Expert tips
Investigate
452 4.2.2 bounce codes to differentiate between truly inactive accounts and temporary issues.
Consider G-Suite billing issues as a potential cause for overquota messages in business accounts.
Marketer view
Marketer from Email Geeks says they opt out Gmail addresses if they get 3-5 consecutive overquota bounces across distinct days, as these mailboxes are often unmonitored.
2020-03-06 - Email Geeks
Marketer view
Marketer from Email Geeks says that given the large storage Gmail provides, a full inbox usually indicates an inactive account. They allow for a few soft bounces before suppression.
Gmail) monitor bounce rates closely. A high rate of even soft bounces suggests that your list contains a significant number of inactive or unengaged contacts, which can trigger spam filters and result in your emails landing in the spam folder for other recipients.
