How to Fix Outlook Error 0x800ccc78

Like other email clients, Microsoft Outlook is prone to software errors, temporary glitches, or third-party software problems. 0x800ccc78 is one of those common Microsoft Outlook errors that may occur due to a number of reasons. Generally, the error indicates a problem with the recipient’s email address in the Reply-To field. However, as said above, it can be due to many reasons. Let’s check this Microsoft Outlook support guide and fix the error. drivingschoolintoronto


As the error indicates an incorrect email address in the Reply-To field, check and correct it if required. You can also remove and enter the entire email address manually. Also, check that your internet connection is working fine. A temporary network glitch can cause Microsoft Outlook to show this error. If there is a temp network problem, wait for it resolve. Otherwise, contact your Internet Service Provider and have it fix your problem. When fixed, open Outlook and check if you can send-receive emails or not. If the error continues to appear, skip to next step.

Exit Windows or MSN Messenger if it is currently running on your desktop. Open Outlook, click Tools, and select Account Settings. When in Account Settings, click the E-mail tab (if it not already clicked), select your email profile, and then click the Change button. When in the Properties window, hit the More Settings button. Click the Outgoing Server tab and check the box next to My outgoing server (SMTP) requires authentication. Also click the button next to Use same settings as my incoming mail server. Click the OK button to exit the window. Click Next and then Finish to exit the window. Close and reopen Outlook. Send a test mail to yourself or to the email address you were previously trying to. It should go through fine.

In case the error still occurs, go back to the More Settings button and check all your settings including server port numbers, server timeouts, your name, email address, and password etc. Save the changes and close the window. Close Outlook too. If nothing works, delete your existing profile and create a new one. In case you are not sure of the settings and details, contact your Internet Service Provider. temp-mail

Download a free registry cleaner tool from a trusted website. Save the file to your computer when prompted. Exit all the windows and locate the downloaded file. Open and run it. Follow the on-screen prompts and install the tool. Reboot your computer if prompted. When done, locate the tool and open it. Before you begin to scan and run a cleanup, create a restore point or back up your registry. It will allow you to undo the changes to your registry (in case something goes wrong with it). When done, run a full scan of your registry and then prompt the tool to fix the registry errors. Make sure that Outlook is closed when you run the tool. When done, exit the tool’s window. Restart your computer if prompted.

Open your antivirus program and update it with latest virus, malware definitions. When done, run a full virus scan of your computer. Prompt the program to delete any infected file brought in the scan results. If your antivirus program did not detect any suspicious item, open your web browser and Google for free online virus scan. I recommend you to run an online virus scan from a website like Trend Micro. Download its HouseCall utility and install it on your computer. When done, install the tool and run a full virus scan. Remove any infected file. Running virus scan from another utility is like taking a second opinion, which is always good in terms of detecting viruses. There are some viruses, Trojans etc. that are capable of dodging your antivirus program. So, you can always run an online virus scan in case you face such a problem.

An over-sized or damaged PST file can also cause the error to occur. Reduce the size of your mailbox by deleting the unnecessary, junk emails etc. If the problem persists, scan and repair the PST file using the SCANPST.exe tool. It is the built-in tool in your Windows operating system. The file by default locates in C: drive> Program Files> Common Files> System> MSMAPI> 1033 or C: drive> Program Files> Common Files> System> Mapi> 1033. If you are using a new Outlook version, check in C: drive> Program Files> Microsoft Office> Office12. Open the tool and scan the PST file. Click the Browse button to select the PST file. The PST file, by default, is located in C: drive> Documents and Settings> Username> Local Settings> Application Data> Microsoft> Outlook.

If everything fails, restore your computer to an earlier date. It will undo all the changes that caused Microsoft Outlook to face the problem. Click the Start button and navigate to Programs> Accessories> Tools> Restore. Select the date when your Outlook was working fine and hit Restore. Confirm the action and wait for the restoration to complete. When done, reboot your computer.


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