I encountered today an error today when using mail merge in Microsoft Word 365 using an excel as source " Error has occured: Catastrophic failure" and i don't know where to fix and why it is happening all of a sudden. Help please.. [Edited by moderator to change references to Word 2020. The year is 2020 but there is no Word 2020. The version Office 365 supplies is an updated version of Word 2019.] A family of Microsoft word processing software products for creating web, email, and print documents. Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question. Okay, so it appears that the problem we're all encountering is similar to one that happened in 2011, as I've found a post by Doug Robbins (of this thread) from that time describing a workaround for the same/a similar issue. I've used the various information to hand, to at least get a Mail Merge completed and, for those who are still having issues, please do the following:- Open Word and click on File -> Advanced -> General and tick Confirm file format conversion on open . Close and re-open Word. Note: This is the most important step (and only needs doing once), as it means Word will ask you for additional information about your information source during the Mail Merge. Also, if you open a previously created Mail Merge document, you may be shown a dialogue box asking if you want to continue. Choose No . Start the Mail Merge wizard and click through until you select your list. Browse for the spreadsheet and open it. Now, you will be prompted to Confirm Data Source . Tick the Show all box and additional options are shown. Scroll down the list until you find MS Excel Worksheets via DDE (*.xls) . Another dialogue window will appear with Entire spreadsheet in it. Click OK . If everything's worked correctly, you should see your data in a window ready for using in your document. I appreciate that this has been mentioned previously by Doug, both now and previously, but sometimes, step-by-step instructions from someone suffering from the problem is what's required. I hope this information helps others, albeit that it's not a permanent fix. Hopefully, the problem is resolved by MS without the need to uninstall Office 2010 and reinstall it. 32 additional answers Anonymous 2020-02-10T07:41:28+00:00 Thanks Doug! I will try to send you the files. 0 comments No comments Report Thanks Doug! I will try to send you the files. Anonymous 2020-02-10T07:38:18+00:00 Hi Tina, Yup I do have an updated version, and i just got a Windows update this morning too. Answering your question: Click Mailing tab>Start Mail Merge>E-mail Messages>Select Recipients>Using an Existing List>select the Excel file, click Open then OK, then the error appears? >>Yes this the exact steps i am doing usually but then recently got the error. Does the issue happen when you use a specific Excel file or all files? >>It's for all the excel files I am using as data source 0 comments No comments Report Yup I do have an updated version, and i just got a Windows update this morning too. Answering your question:

Click Mailing tab>Start Mail Merge>E-mail Messages>Select Recipients>Using an Existing List>select the Excel file, click Open then OK, then the error appears? >>Yes this the exact steps i am doing usually but then recently got the error. Does the issue happen when you use a specific Excel file or all files? >>It's for all the excel files I am using as data source Anonymous 2020-02-10T07:22:52+00:00 Hi Wendy, Sorry for the trouble caused by this issue. I understand the issue happens when you use an existing list(Excel file) when using Mail Merge. To narrow down if the issue only happens with a specific Excel file, I suggest you create another test Excel file, then use the test file to do mail merge again and check if issue happens. I also suggest you create a new Word document and try to use mail merge again. Also, ensure to use the latest version of Office. In Word, you may click File>Account>Update Options>Update Now, see if you already have the latest version or if there is new version available. If the error message still appears, try Online Repair Office with the steps in this article . If issue persists, I'd like to confirm information below to help you further troubleshoot the issue: 1.Before the error message appears, what are your detailed steps?(if below are not your steps, please clarify yours.) Click Mailing tab>Start Mail Merge>E-mail Messages>Select Recipients>Using an Existing List>select the Excel file, click Open then OK, then the error appears? 2.Does the issue happen when you use a specific Excel file or all files? 3.In Word, please click File>Account, capture a full screenshot of Product Information from the right side of the window. 4.Please provide a screenshot of the error message. Thanks for your time and effort. Best regards, Tina 0 comments No comments Report Sorry for the trouble caused by this issue. I understand the issue happens when you use an existing list(Excel file) when using Mail Merge. To narrow down if the issue only happens with a specific Excel file, I suggest you create another test Excel file, then use the test file to do mail merge again and check if issue happens. I also suggest you create a new Word document and try to use mail merge again. Also, ensure to use the latest version of Office. In Word, you may click File>Account>Update Options>Update Now, see if you already have the latest version or if there is new version available. If the error message still appears, try Online Repair Office with the steps in this article . If issue persists, I'd like to confirm information below to help you further troubleshoot the issue: 1.Before the error message appears, what are your detailed steps?(if below are not your steps, please clarify yours.) Click Mailing tab>Start Mail Merge>E-mail Messages>Select Recipients>Using an Existing List>select the Excel file, click Open then OK, then the error appears? 2.Does the issue happen when you use a specific Excel file or all files? 3.In Word, please click File>Account, capture a full screenshot of Product Information from the right side of the window. 4.Please provide a screenshot of the error message. Thanks for your time and effort. Doug Robbins - MVP - Office Apps and Services • 323.4K Reputation points • MVP • Volunteer Moderator 2020-02-10T07:18:08+00:00 If you send me a copy of the mail merge main document and the Excel Data Source, referencing this thread in the covering email message, I will investigate the issue. 0 comments No comments Report If you send me a copy of the mail merge main document and the Excel Data Source, referencing this thread in the covering email message, I will investigate the issue.