Cannot send attached file in Outlook

Dear Jannette,

Good day, and thank you for reaching out to the Q&A Forum.

I’m sorry to hear that Outlook is failing when you try to send attachments to multiple users. I understand how inconvenient this can be, especially when the file is only around 18 MB and the error suggests the attachment failed to upload. As a forum moderator, I genuinely wish I could directly access your Outlook profile, mailbox settings, or Exchange configuration to diagnose and fix this for you. However, our role here is limited to providing general guidance and possible solutions that users can try from their side. 

From my research, since the file is coming from a shared drive, Outlook may have trouble uploading it if there is a temporary network issue, permission issue, file lock, or sync/access problem. To better understand the situation, could you please share a few more details:

• Are you using a personal account or a business account managed by an organization?
• Does the error happen with only this file or all attachments?
• Can you send the file if it is copied from the shared drive to your local computer first?
• How many recipients are included?
• Is the shared drive a network drive, SharePoint/OneDrive sync folder, or another file server?

Once you share these details, I will be in a better position to determine whether this is caused by an Outlook upload failure, a shared drive access issue, an attachment / message size limit, or an Exchange policy, and provide you with more targeted guidance.

Thank you for your patience and understanding. Looking forward to your reply.

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