Unable to Import Customers into Microsoft Bookings Using CSV (All Formats Fail)

Teun Bogers 5 Reputation points

I am experiencing persistent issues with importing customers into Microsoft Bookings using CSV files, and I would like clarification on the correct and supported format.

Context:

I am trying to import a large list of customers into Microsoft Bookings via CSV so that they can be reused when creating appointments. What I tried: I tested multiple CSV formats: 1. Outlook-style CSV Columns used: Title, Last Name, E-mail Address, Mobile Phone, etc. This format previously worked for me, but now results in an error when importing into Bookings.

  1. Simplified Bookings format Columns used: DisplayName, EmailAddress, Phone, Notes This format also results in an error such as: "The file format is not correct"
  2. Alternative formats and variations I also tested: - Using “MobilePhone” instead of “Phone” - Combining different column names - Removing optional fields - Ensuring consistent number of columns in every row Despite all of this: - The file structure is consistent - No extra columns or trailing separators are present - Files are saved as CSV UTF-8 (comma delimited) The problem: All CSV formats I try result in an import error in Microsoft Bookings. It is unclear which format is actually supported.

Questions:

  1. What is the exact, currently supported CSV format for importing customers into Microsoft Bookings?
  2. Is the CSV import feature still fully supported, or has it changed recently?
  3. Does Microsoft Bookings still support Outlook-style contact CSV files?
  4. Are there specific hidden requirements (such as required fields or exact column naming) that are not documented?
  5. Is there a known issue or limitation with CSV import in Bookings?

Additional note: Based on testing, the CSV import functionality appears inconsistent or unreliable, even when using clean and valid CSV files. Any clarification on the correct format or recommended approach would be very helpful. Thank you.

  1. Nick Klee 0 Reputation points

    This basic feature is most definitely broken. It doesnt work with an Outlook generated CSV export of contacts. It doesn't work with a clean file. It doesn't even work with the sample file of how to create a CSV referenced on your website.

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2 answers

  1. Teun Bogers 5 Reputation points

    Hi @Ana Le ,

    Thank you for your detailed and helpful response. I followed all of your recommendations step by step, but unfortunately the issue still persists. Here is what I tested:

    1. I created a completely new CSV file with only 1–2 test contacts (minimal dataset).
    2. I used the exact Outlook contact field names (e.g. "Title", "Last Name", "E-mail Address", "Mobile Phone") without renaming any columns.
    3. I ensured that all mandatory fields (name and email) contain valid values.
    4. I saved the file as CSV UTF-8 (comma delimited).
    5. I tested the import in an InPrivate/Incognito browser session to rule out caching issues. Despite this, I still receive the following error message: "There was a problem. The file format is not correct. Please make sure the file is exported in the Outlook CSV format."

    This happens even with a very small and clean test file. Based on your explanation, this suggests that the issue may not be related to the CSV format itself, but rather: - a potential service-side issue, - a regional inconsistency, - or a limitation/bug within Microsoft Bookings. Additional information: - I am using Microsoft Bookings within a Microsoft 365 Business tenant. - The issue occurs even with a file containing only 1–2 contacts. - I tested multiple CSV structures (Outlook-style and simplified formats), all with the same result.

    One additional question: Since I am working in a Dutch (NL) Microsoft 365 environment, could the issue be related to localization? For example: - Do the column names need to be in Dutch (e.g. "Voornaam", "Achternaam") instead of English? - Or does Microsoft Bookings always expect the original English Outlook CSV field names regardless of language settings?

    At this point, it seems that the CSV import functionality is either not functioning correctly in my environment or behaving inconsistently.
    Could you confirm:
    If escalation to Microsoft support would be recommended in this case? I appreciate your help and look forward to your guidance.
    Kind regards, Teun

    1. Ana Le 1,105 Reputation points • Independent Advisor

      Thank you for the detailed follow-up and for taking the time to perform all of those additional tests @Teun.

      Based on the results you shared, I agree that this no longer appears to be a simple CSV formatting issue. Since the error occurs with:

      • A minimal test file containing only 1–2 contacts
      • Outlook-style CSV headers
      • UTF-8 CSV format
      • Multiple CSV structures
      • An InPrivate browser session

      you have already covered the most common causes of import failures.

      Regarding your localization question, I am not aware of any Microsoft documentation indicating that Microsoft Bookings requires localized column names based on the tenant language. In general, the import process has historically been associated with Outlook-exported CSV files, and Outlook itself handles localization when exporting contacts. Therefore, I would not expect manually translating the headers to Dutch (for example, "Voornaam" or "Achternaam") to be a requirement.

      At this point, because:

      • The issue persists with multiple valid test files,
      • The error message continues to reference Outlook CSV format despite using that format,
      • And there is no publicly documented validation guide that explains the exact schema requirements,

      it would be reasonable to suspect a service-side issue, a tenant-specific problem, or a product defect that cannot be verified from the Community side.

      For that reason, I would recommend opening a support request with Microsoft 365 Support. The support team has access to backend diagnostic tools and service telemetry that are not available in the Community forum and can determine whether the import requests are failing due to a tenant-specific issue or a known product problem. You can follow the guidance in here: Get Support | Microsoft 365 for business

      When contacting support, I would suggest providing:

      • A sample CSV file that reproduces the issue
      • A screenshot of the error message
      • The time and date of a recent failed import attempt
      • Confirmation that the issue occurs with both Outlook-style and simplified CSV formats

      This should help the support engineer investigate the issue more efficiently.

      Please let me know if you receive any findings from Microsoft Support, as that information may also help other community members who encounter the same behavior.

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  2. Ana Le 1,105 Reputation points • Independent Advisor

    Hello @Teun,

    Thank you for providing such a detailed description of the issue and the troubleshooting steps you have already performed.

    Based on the information currently available, Microsoft Bookings does still support importing customer data through CSV files. However, Microsoft does not provide a comprehensive public document that clearly defines all supported CSV schemas or validates every accepted column format.

    Historically, Bookings has accepted customer imports based on Outlook contact CSV formats, and Microsoft moderators have continued to reference Outlook-style CSV files as the recommended format for customer imports. Outlook CSV format guidance

    For troubleshooting, I would recommend:

    1. Create a new CSV file using only a very small test set (for example, 1–3 contacts).
    2. Use the Outlook contact field names exactly as exported by Outlook, without renaming the headers.
    3. Ensure that at least the contact name and email fields contain valid values.
    4. Save the file as CSV UTF-8 (Comma delimited) (*.csv).
    5. Try importing the file from a different browser session (InPrivate/Incognito mode) to rule out cached portal issues.

    Regarding your specific questions:

    • CSV customer import remains available in Microsoft Bookings.
    • Outlook-style contact CSV files are still the format most commonly referenced by Microsoft support resources.
    • Custom columns that are not part of the supported contact fields are generally not imported into Bookings.
    • There is no recently published announcement indicating that customer CSV import has been deprecated.
    • If even a minimal Outlook-exported CSV file fails with the message "The file format is not correct", this may indicate a service-side issue, a regional service inconsistency, or a product defect rather than a problem with the CSV structure itself.

    To help narrow this down further, could you share:

    • A screenshot of the complete error message. Please remove any personal information before sharing it.
    • Whether you are using Microsoft Bookings from a Microsoft 365 Business or Enterprise tenant.
    • Whether the issue occurs with a CSV containing only a single test contact.

    That additional information may help determine whether this is a formatting issue or a problem that requires escalation to Microsoft Support for further investigation.

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