You may have noticed a change when attaching files in the new Outlook for Windows. The traditional method of attaching a copy has been joined by a new option to upload a file to the cloud. This change is part of Microsoft’s integration of cloud storage into the email workflow. This article explains the difference between these two methods and when to use each one.
Key Takeaways: Outlook Attachment Methods
- Attach as copy: This method embeds a duplicate of the file into the email itself, which is the traditional way Outlook has always worked.
- Upload and share: This new method uploads the file to your OneDrive and inserts a secure link into the email instead of the file.
- Attachment icon with cloud: A small cloud icon on the attachment button indicates the file will be uploaded to OneDrive by default.
Understanding the Two Attachment Methods
The new Outlook client, often referred to as the “new Outlook” or “One Outlook,” is built on a modern web platform. A core design principle is to use cloud services like OneDrive and SharePoint more deeply. The attachment change reflects this shift from local file handling to cloud-centric collaboration.
When you choose Attach as copy, Outlook creates a duplicate of your file and attaches it to the email message. The recipient downloads this copy from the email server. This method is familiar and works with any email client the recipient uses. The file size is limited by your email provider’s attachment limits, typically 20-25 MB.
When you use Upload and share, Outlook uploads the file to your OneDrive. It then places a sharing link to that file in the email body. The recipient clicks the link to view or download the file from OneDrive. This method bypasses traditional size limits and allows for real-time co-authoring if you grant edit permissions.
How the Default Method is Chosen
Outlook tries to predict the best method. For smaller files, it may default to Attach as copy. For larger files, it will default to Upload and share. You can see which method will be used before you send. An attachment with a cloud icon next to it is a link. An attachment with a paperclip icon is a traditional copy.
How to Choose Between Upload and Attach as Copy
The method you select depends on your goal for the file. Follow these steps to control how your file is sent.
- Compose a new email
Click New Mail in Outlook to start a new message. - Click the Attach button
Click the paperclip icon or the Attach button on the message ribbon. - Select your file
Browse your computer or OneDrive and select the file you want to send. After selection, Outlook will show a preview of the attachment in the message body. - Change the attachment type if needed
Click the dropdown arrow on the attached file’s preview. You will see two options: “Upload and share” and “Attach as copy.” Select your preferred method. - Set permissions for cloud attachments
If you chose Upload and share, click the attached link’s dropdown menu. Choose between “Recipients can edit” or “Recipients can view” to control access.
Setting a Global Preference
You can change the default attachment behavior for all emails.
- Open Outlook Settings
Click the gear icon in the top-right corner of the new Outlook window. - Go to Mail > Attachments
In the Settings pane, select Mail, then select Attachments from the list. - Choose your default
Under “When attaching files,” select your preference: “Always upload and share” or “Always attach as copy.” You can also choose “Ask me every time” for manual control.
Common Mistakes and Limitations to Avoid
Recipients Cannot Open My Cloud Attachment
This happens if the recipient lacks permission to access your OneDrive. When you upload a file, Outlook sets sharing permissions. If the recipient is outside your organization, ensure the link is set to “Anyone with the link” or that their specific email address has access. Check the link permissions by clicking the dropdown on the attachment in your draft.
I Need to Send a File to Someone Without Internet Access
Do not use Upload and share for this scenario. The recipient must be online to access a OneDrive link. Always use Attach as copy for offline recipients, as the file is embedded directly in the email they can download later.
The Attachment is Too Large for Email
If your file exceeds your mail server’s limit, Attach as copy will fail. You must use Upload and share for large files. OneDrive links have a much higher effective size limit, often up to 250 GB depending on your subscription.
I Want to Track Who Opens My File
You cannot track opens with Attach as copy. With Upload and share, you can see if recipients have accessed the link. Go to your OneDrive online, find the file, and click the information panel to see activity.
Upload and Share vs Attach as Copy: Key Differences
| Item | Upload and Share | Attach as Copy |
|---|---|---|
| File location | Stored in your OneDrive | Embedded in the email |
| Size limit | Very high (up to 250 GB) | Low (typically 20-25 MB) |
| Recipient access | Requires internet to download | File is in the email |
| Collaboration | Allows real-time co-editing | Recipients work on separate copies |
| Storage impact | Uses your OneDrive quota | Uses your email server quota |
| Security control | You can change permissions later | Permissions fixed after sending |
You can now choose the best method for sharing files in Outlook. Use Attach as copy for small, final documents sent to anyone. Use Upload and share for large files or when you need collaboration. Try changing the default setting in Mail > Attachments to match your most common workflow. For advanced control, use the Outlook web app to attach files directly from SharePoint libraries.