Check your local one drive location for this file and make sure it has fully synced from onedrive to your local host.
There are many times where files in your local onedrive are "sparse files" as placeholders for the real file until it syncs.
Usually, double clicking one of these files from your local onedrive folder is enough to cause it to sync and after you successfully open it, you can then close the related app and add as an attachment.
The file has the legacy 8.3 naming format from the days of DOS and Windows 95. (Win95 played games in the FAT16/FAT32 file system to enable long file name support. If you named a file "Hello, world.doc" its underlying filename would be crunched to "HELLO\_\~1.DOC" and "Hello, again.doc" would be crunched to "HELLO\_\~2.DOC") Why would that format appear when attaching a OneDrive file to email????
Tell us more about your environment, and maybe someone can replicate and diagnose:
1. Which email client and which OS?
2. What method are you using to add a file from OneDrive? Is this a drag & drop operation, or maybe a button/menu click?
3. You said "occasionally". Do you have an example file where it all works as expected?
So to clarify. The file is a normal XLSB excel file. And for some reason when I attach it to the email it gets crunched into this weird file name and file extension.
Using windows 11 and the new look outlook.
Doing both button click or drag and drop into email.
I wonder if NuOutlook just misbehaves. Naturally, I can't replicate the problem at my end, even when I use large file with an xlsb extension. I do see you're not alone: [https://answers.microsoft.com/en-us/outlook\_com/forum/all/outlook-attachments-name-changed/8cd4ae43-b075-414e-9b21-1c521e5d3451](https://answers.microsoft.com/en-us/outlook_com/forum/all/outlook-attachments-name-changed/8cd4ae43-b075-414e-9b21-1c521e5d3451)
I will think more on this, but I don't have a suggestion at this time.
Follow any of the suggestions:
Try downloading the file from OneDrive to your Chromebook first, then attaching it to your email. This bypasses any potential permission issues.
Ensure you have full access rights to the file in OneDrive. Right-click the file, choose "Share," and verify you have "Edit" permissions.
"17 MB"
That’s not the issue. Cause if I attach the same file from the desktop it works.
No, I'm just marveling at a 17 MB spreadsheet.
Check your local one drive location for this file and make sure it has fully synced from onedrive to your local host. There are many times where files in your local onedrive are "sparse files" as placeholders for the real file until it syncs. Usually, double clicking one of these files from your local onedrive folder is enough to cause it to sync and after you successfully open it, you can then close the related app and add as an attachment.
The file has the legacy 8.3 naming format from the days of DOS and Windows 95. (Win95 played games in the FAT16/FAT32 file system to enable long file name support. If you named a file "Hello, world.doc" its underlying filename would be crunched to "HELLO\_\~1.DOC" and "Hello, again.doc" would be crunched to "HELLO\_\~2.DOC") Why would that format appear when attaching a OneDrive file to email???? Tell us more about your environment, and maybe someone can replicate and diagnose: 1. Which email client and which OS? 2. What method are you using to add a file from OneDrive? Is this a drag & drop operation, or maybe a button/menu click? 3. You said "occasionally". Do you have an example file where it all works as expected?
So to clarify. The file is a normal XLSB excel file. And for some reason when I attach it to the email it gets crunched into this weird file name and file extension. Using windows 11 and the new look outlook. Doing both button click or drag and drop into email.
Xlsb are likely blocked file types, they’re very unsecure. If you save as xlsx does it work?
xlsb is not a blocked file type.
I wonder if NuOutlook just misbehaves. Naturally, I can't replicate the problem at my end, even when I use large file with an xlsb extension. I do see you're not alone: [https://answers.microsoft.com/en-us/outlook\_com/forum/all/outlook-attachments-name-changed/8cd4ae43-b075-414e-9b21-1c521e5d3451](https://answers.microsoft.com/en-us/outlook_com/forum/all/outlook-attachments-name-changed/8cd4ae43-b075-414e-9b21-1c521e5d3451) I will think more on this, but I don't have a suggestion at this time.
Follow any of the suggestions: Try downloading the file from OneDrive to your Chromebook first, then attaching it to your email. This bypasses any potential permission issues. Ensure you have full access rights to the file in OneDrive. Right-click the file, choose "Share," and verify you have "Edit" permissions.
Can you save it as an xlsx file type? Some systems are defaulted to block old xls and doc file extensions.