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M365 Copilot-created file placed at unreachable URL: sandbox:/mnt/data

Maria Mingallon 195 Reputation points
2025-07-08T00:44:08.3766667+00:00

We are encountering a recurring issue where Microsoft 365 Copilot creates files that are saved to an unreachable URL: sandbox:/mnt/data. This behavior has been observed in multiple contexts:

  • When using M365 Copilot chat
  • When interacting with Microsoft Copilot agents via browser app or Teams
  • When working within the Notebook experience

This issue prevents users from accessing the generated files, disrupting workflows and causing confusion.

A similar topic was previously raised in the Microsoft Answers forum (https://answers.microsoft.com/en-us/msoffice/forum/all/m365-copilot-created-file-placed-at-unreachable/54cedad9-20fe-4b67-a9e3-11ea0bf1dd60?page=1&messageId=b68870a6-c171-4bc3-a09b-6ebe2533be08), but it has not been successfully addressed by Microsoft so far.

We are raising this again in hopes of receiving a definitive explanation and resolution. Specifically, we would like to understand:

  • Why are files being saved to sandbox:/mnt/data?
  • Is this expected behavior or a bug?
  • What steps can be taken to retrieve or redirect these files to an accessible location?

Thank you for your support.

Microsoft Copilot | Microsoft 365 Copilot | Development

3 answers

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  1. Devarsh Shah 0 Reputation points
    2026-02-16T18:50:38.4633333+00:00

    from reportlab.lib.pagesizes import letter

    from reportlab.pdfgen import canvas

    from reportlab.lib import colors

    def create_st_events_pdf(filename):

    c = canvas.Canvas(filename, pagesize=letter)

width, height = letter

# --- Title Section ---

c.setFont("Helvetica-Bold", 30)

c.drawCentredString(width / 2, height - 100, "ST EVENTS")



c.setFont("Helvetica-Oblique", 16)

c.setFillColor(colors.darkblue)

c.drawCentredString(width / 2, height - 130, "Shah & Talsaniya Event Company")

c.setFillColor(colors.black)

# --- Divider Line ---

c.setLineWidth(2)

c.line(50, height - 150, width - 50, height - 150)

# --- About Us Section ---

c.setFont("Helvetica-Bold", 18)

c.drawString(50, height - 200, "About Us")



c.setFont("Helvetica", 12)

text_object = c.beginText(50, height - 230)

text_object.textLines("""

Welcome to ST Events. We are dedicated to making your celebrations unforgettable.



We proudly accept orders for functions and festivals across ALL INDIA.

Whether it is a grand wedding, a corporate event, or a religious festival,

our team is ready to serve you anywhere in the country.

""")

c.drawText(text_object)

# --- Partners Section ---

c.setFont("Helvetica-Bold", 18)

c.drawString(50, height - 330, "Our Partners")

c.setFont("Helvetica", 14)

c.drawString(70, height - 360, "1. Shah Devarsh")

c.drawString(70, height - 385, "2. Talsaniya Alay")

# --- Contact Section ---

c.setFillColor(colors.whitesmoke)

c.rect(40, height - 550, width - 80, 120, fill=1, stroke=0)

c.setFillColor(colors.black)

c.setFont("Helvetica-Bold", 20)

c.drawCentredString(width / 2, height - 480, "CONTACT US TODAY")

c.setFont("Helvetica-Bold", 14)

c.drawCentredString(width / 2, height - 510, "Devarsh: +91 94273 19101")

c.drawCentredString(width / 2, height - 530, "Alay: +91 96649 41550")

# --- Footer ---

c.setFont("Helvetica-Oblique", 10)

c.drawCentredString(width / 2, 50, "ST Events - Making Moments Memorable")

c.save()

    Create the PDF

    create_st_events_pdf("ST_Events_Profile.pdf")

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    4 people found this answer helpful.
  2. Pierre Baret 10 Reputation points
    2025-12-11T16:01:51.6+00:00

    I faced the same issue discussing with chat about a coding project, at some point I asked to generate the project after all the back and forth discussion and he generated it under "/mnt/data/image_reviewer" which does not exist on my windows laptop obviously.

    My work around was the following prompt: "can you zip the generated repo so I can download it"

    it worked like a charm.

    Was this answer helpful?

    4 people found this answer helpful.
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