Fix: qbmapi64 Out of Memory Error – Causes & Solutions

If you rely on QuickBooks to manage your daily finances, you expect smooth performance when emailing invoices, estimates, or reports. However, encountering the qbmapi64 out of memory error can bring your workflow to a sudden halt. This frustrating issue typically appears when QuickBooks attempts to send an email via Microsoft Outlook or another MAPI-compliant client, but the system runs out of allocated memory. Before you panic, know that this is a solvable problem. For immediate assistance, you can reach the QuickBooks support team at +1(800) 780-3064. In this comprehensive guide, we will break down what this error means, why it happens, and step-by-step solutions to get you back on track—also covering related issues like QuickBooks Not Sending Invoices and QuickBooks Invoices Not Being Received.

What Is the qbmapi64 Out of Memory Error?

The qbmapi64 out of memory error is a Windows-based error that occurs within the QuickBooks MAPI (Messaging Application Programming Interface) subsystem—specifically the 64-bit version (qbmapi64.dll). This DLL file acts as the bridge between QuickBooks and your email client (most often Microsoft Outlook). When QuickBooks cannot allocate enough RAM to process the email-sending request, the error pops up, preventing invoice delivery.

Common symptoms include:

• QuickBooks freezing when you click "Send" on an invoice.

• An error message stating "Out of memory" or "MAPI error."

• Outlook not opening or responding when triggered by QuickBooks.

• QuickBooks MAPI Keeps Asking for Password repeatedly, even after entering the correct credentials.

This error is not a hardware failure but rather a resource allocation or configuration glitch. It becomes more frequent when sending large PDF attachments, multiple invoices at once, or after a Windows or Outlook update.

Top Reasons Behind the qbmapi64 Out of Memory Error

Understanding the root causes helps you apply the right fix. Here are the most common reasons:

1. Insufficient System Resources – QuickBooks and Outlook together consume large amounts of RAM. If you have other heavy applications open (like Chrome with 20 tabs), the memory may run out.

2. Corrupt MAPI Profile – Your Outlook profile can become corrupted, leading to memory allocation failures.

3. Outdated QuickBooks or Outlook – Mismatched versions or missing patches often trigger QuickBooks delivery server down behavior.

4. Large Attachments or Email Threads – Sending invoices with high-resolution logos or very long email histories can exceed memory limits.

5. Add-in Conflicts – Third-party Outlook add-ins (e.g., Zoom, Grammarly) can conflict with qbmapi64.dll.

6. Windows Registry Issues – Incorrect registry keys for MAPI or QuickBooks can limit memory allocation.

7. User Account Control (UAC) or Permissions – QuickBooks may not have sufficient privileges to access Outlook’s memory space.

Full Solutions to Resolve qbmapi64 Out of Memory Error

Follow these detailed, step-by-step solutions in order. Most users resolve the issue by step 3.

Solution 1: Restart and Free Up System Memory

Before diving into complex fixes, perform a clean memory reset:

• Save all work and close QuickBooks, Outlook, and your web browser.

• Open Task Manager (Ctrl + Shift + Esc) and check the "Memory" column. End any unnecessary processes using high RAM.

• Restart your computer completely. This clears the page file and releases memory leaks.

• Open only QuickBooks and Outlook, then try sending the invoice again.

If the error persists, proceed to the next solution.

Solution 2: Repair QuickBooks MAPI Components

Corrupt MAPI files are a leading cause of QuickBooks Not Sending Invoices.

1. Close QuickBooks and Outlook.

2. Open the Run dialog (Windows + R), type Control Panel, and press Enter.

3. Go to Programs and Features → Select QuickBooks → Click Uninstall/Change.

4. Choose Repair (not uninstall). Follow the on-screen prompts.

5. After repair, restart your PC.

6. Open QuickBooks, go to Edit → Preferences → Send Forms → My Preferences.

7. Select Outlook (or MAPI) as your email client and click OK.

For persistent QuickBooks MAPI Keeps Asking for Password, also try:

• Open Outlook → File → Account Settings → Account Settings → Select your email → Change → Re-enter password and check "Remember password."

Solution 3: Create a New Outlook Profile

A fresh MAPI profile often eliminates memory errors:

1. Close Outlook and QuickBooks.

2. Open Control Panel → Mail (or Mail (Microsoft Outlook)).

3. Click Show Profiles → Add → Give it a name (e.g., "QuickBooksProfile").

4. Set up your email account on this new profile.

5. Under "When starting Microsoft Outlook," select Prompt for a profile.

6. Restart Outlook and select the new profile. Then open QuickBooks and test sending an invoice.

Solution 4: Disable Outlook Add-ins Temporarily

Conflicting add-ins can trigger QuickBooks Invoices Not Being Received or the out-of-memory error.

1. Open Outlook → File → Options → Add-ins.

2. At the bottom, set "Manage" to COM Add-ins → Click Go.

3. Uncheck all add-ins except any QuickBooks-related ones (if listed).

4. Click OK and restart Outlook.

5. Test sending an invoice. If it works, re-enable add-ins one by one to find the culprit.

Solution 5: Increase Virtual Memory (Page File)

Sometimes Windows simply needs more swap space.

1. Right-click This PC → Properties → Advanced system settings.

2. Under Performance → Settings → Advanced → Virtual memory → Change.

3. Uncheck "Automatically manage paging file size."

4. Select your system drive (C:), choose Custom size, and set:

   • Initial size: 1.5 x your RAM (e.g., for 8GB RAM = 12288 MB)

   • Maximum size: 3 x your RAM (e.g., 24576 MB)

5. Click Set → OK → Restart your computer.

Solution 6: Repair Windows MAPI and QuickBooks Delivery Server

If you suspect QuickBooks delivery server down is the real issue:

1. Download and run the QuickBooks Tool Hub (official Intuit tool).

2. Go to Program Problems → QuickBooks MAPI Fix.

3. Then go to Connection Issues → QuickBooks Delivery Server Repair.

4. Restart your PC and re-configure email settings in QuickBooks.

Solution 7: Reinstall QuickBooks with MAPI Components

As a last resort (after backing up company files):

1. Uninstall QuickBooks via Control Panel → Programs and Features.

2. Use the Clean Install Tool from the QuickBooks Tool Hub to remove all leftover files.

3. Restart your PC.

4. Reinstall QuickBooks using the latest version from your Intuit account.

5. During installation, ensure the "MAPI" option is selected (if presented).

How to Prevent Future qbmapi64 Out of Memory Errors

Prevention is better than cure. Follow these best practices:

• Keep Outlook and QuickBooks updated – Turn on automatic updates.

• Limit attachment sizes – Keep invoice PDFs under 5MB. Use file compression for large attachments.

• Send invoices in batches – Do not send 50+ invoices at once. Use QuickBooks’ "Send Later" feature and send 10 at a time.

• Regularly clean Outlook – Archive or delete old emails and empty the “Deleted Items” folder weekly.

• Monitor RAM usage – Use Windows Task Manager to ensure at least 2GB free before sending emails from QuickBooks.

When to Seek Professional Help

If you have tried all seven solutions and still face QuickBooks Not Sending Invoices or the qbmapi64 out of memory error, there may be deeper Windows registry corruption or a conflict with antivirus software (e.g., McAfee, Norton blocking MAPI). In such cases, do not attempt manual registry edits unless you are an IT professional. Instead, call the dedicated support team at +1(800) 780-3064. They can remotely diagnose and repair the issue in minutes, saving you hours of frustration. For any recurring MAPI or QuickBooks delivery server down suspicions, that same number—+1(800) 780-3064—connects you directly to certified QuickBooks Enterprise and ProAdvisor technicians.

Final Thoughts

The qbmapi64 out of memory error is a common but resolvable roadblock that stops QuickBooks from emailing invoices. By methodically freeing up system memory, repairing MAPI components, recreating your Outlook profile, and adjusting virtual memory, you can restore full email functionality. Remember that related issues like QuickBooks MAPI Keeps Asking for Password and QuickBooks Invoices Not Being Received often stem from the same root cause—a corrupted MAPI connection. Apply the fixes in the order given, and don’t hesitate to reach out to +1(800) 780-3064 if you need expert eyes on your system. With this guide, you can eliminate the error and keep your invoicing running smoothly.

Frequently Asked Questions (FAQs)

Q1: Why does QuickBooks keep asking for my Outlook password?

A: This is typically caused by a corrupt MAPI profile or saved password mismatch. The error QuickBooks MAPI Keeps Asking for Password often accompanies the out-of-memory error. Solution: Delete and recreate your Outlook profile (see Solution 3) and ensure your email password is saved in Windows Credential Manager. If issues persist, contact +1(800) 780-3064 for live troubleshooting.

Q2: Can a slow internet connection cause this error?

A: Not directly. The error is memory-based, not network-based. However, if you are experiencing QuickBooks Invoices Not Being Received, it could be a separate issue like SMTP settings or ISP blocking. The memory error must be fixed first; then check your email server status.

Q3: Does this error affect QuickBooks Desktop for Mac?

A: No. qbmapi64 is Windows-specific. Mac users may see “MAPI error” but the fixes are different (involving Apple Mail or Outlook for Mac settings).

Q4: How do I know if the QuickBooks delivery server is actually down?

A: Intuit’s email delivery server status can be checked via the official Intuit Status Page. But the qbmapi64 out of memory error is local to your computer, not a server outage. If the server were down, you’d see a different error like “QuickBooks was unable to send email.”

Q5: Will updating QuickBooks to the latest release fix this?

A: Yes, often. Intuit regularly patches MAPI-related memory leaks. Go to Help → Update QuickBooks → Update Now. Install any available updates and restart your system.