SharePoint folder download stops at ~40 MB for external users – files corrupted or incomplete

Question

SharePoint folder download stops at ~40 MB for external users – files corrupted or incomplete

ERNIYAZOV SARVARBEK 0

Title: SharePoint folder download stops at ~40 MB for external users – files corrupted or incomplete

Details:

I am an external user (student at Chonnam National University, Korea) who was granted access to a shared OneDrive/SharePoint folder by a researcher at University Health Network (UHN), Canada.

The shared folder contains two subfolders (Fall and NonFall) with a large number of JPG image files. I have been trying to download these folders for several weeks, but I am facing the following issues:

Problem 1 – Download stops mid-way:

When I click "Download" on the Fall or NonFall folder, the browser starts downloading a .zip file but stops at around 40 MB. The download speed drops to 0 KB/s and never recovers. I have tried this on multiple browsers (Chrome, Edge) and on a stable wired university network connection.

Problem 2 – Corrupted zip archives:

In earlier attempts, the downloaded zip files either:

Contained only a subset of files (missing most folders), or
Contained placeholder _Error.txt files instead of actual JPG images

7-Zip reports "Errors: 1" when opening these archives.

Environment:

External user accessing a UHN SharePoint/OneDrive share
Connected via wired university network (stable, high-speed)
Tried on Chrome and Edge browsers
SharePoint link format: universityhealthnetwork-my.sharepoint.com

Question:

Is there a known limitation on SharePoint that causes large folder downloads to fail or produce corrupted zips for external users? Is there a recommended workaround (e.g., downloading subfolders individually, using OneDrive sync client, or another method)?

Thank you.

0 comments

2 answers

Your answer

Answer 1

I have already tried downloading subfolders individually (Fall1, Fall2, etc.), but the download still stalls at around 40 MB and drops to 0 KB/s regardless of subfolder size. The issue persists across Chrome and Edge on a stable wired university network.

The corrupted zip issue (placeholder _Error.txt files) also occurred when downloading individual subfolders, not just the full folder.

Is there a way to resume interrupted downloads from SharePoint, or a method that does not rely on browser-based zip streaming? For example, is it possible to use the OneDrive sync client as an external guest user without a Microsoft 365 license?

Answer 2

Doris V 1,700 Microsoft External Staff Moderator

Dear @ERNIYAZOV SARVARBEK,

From your description, I understand that you are an external user accessing a shared SharePoint/OneDrive folder, and when you try to download the folder as a ZIP file, the download starts but stops at around 40 MB. You also mentioned that some downloaded ZIP files are incomplete or contain _Error.txt files instead of the expected images. To better assist, could you please confirm following information:

Do you see a “Sync” button when you open the shared folder?
Approximately how many files are in the folder, and how large is the total size?
Are you using a work/school account to sign in, or a personal email account?
Does the issue happen with all folders, or only specific ones?
Are you able to download individual JPG files successfully, or do they fail as well?
Does the download always stop at around 40 MB, or does the stopping point vary?
Do you see any message in the browser?
If you try downloading a very small folder (few files only), does it complete successfully?

In the meantime, I recommend the following options:

1/ Download in very small batches.

Select only 20–30 images at a time (not whole folders), download as zip. Small enough to complete before timeout.

2/ Use OneDrive Sync Client External/guest users can use the OneDrive desktop app without a Microsoft 365 license. Open the shared link in browser > click "Add shortcut to My OneDrive" or "Sync" OneDrive app syncs files in the background, resuming automatically if interrupted Much more reliable than browser zip downloads

3/ Ask the sharer to use SharePoint "Send to" / direct file links

The researcher at UHN can:

Re-share as individual files with direct download links

Use Microsoft Teams to share the files (different download path, more stable)

Upload to a neutral service for one-time transfer

About resume support: Currently, SharePoint browser-based folder downloads do not support resuming if interrupted, so the download must usually be restarted.

Please understand that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution. Your detailed response will help us diagnose and investigate the issue more efficiently.

I truly appreciate your patience and understanding. If I misunderstood what you’re looking for, feel free to let me know or share a screenshot. I’d be happy to help further!

Thank you for your cooperation.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

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ERNIYAZOV SARVARBEK 0 Reputation points

2026-05-27T08:04:10.83+00:00
Thank you for your detailed response. Here are the answers to all your questions:

Sync button: No, I do not see a "Sync" button when opening the shared folder. Only "Share", "Copy link", and "Download" buttons are visible.

File count and total size: The dataset has two main folders:

Fall: 35 subfolders, each containing ~730–1,900 JPG files. Total approximately 35,000+ files.

NonFall: 9 subfolders (ADL1–ADL9), each containing ~1,191–4,053 JPG files. Total approximately 22,000+ files.

Each JPG file is approximately 8–9 KB.

Estimated total size: several GB.

Account type: I am signed in with my university work/school account: ******@jnu.ac.kr (Chonnam National University, Korea). I am an external guest user accessing a folder shared by a researcher at University Health Network (UHN), Canada.

Which folders affected: The issue happens with ALL folders — both Fall and NonFall, and all their subfolders, regardless of size.

Individual JPG files: YES — I successfully downloaded individual JPG files. I selected multiple files inside the ADL9 subfolder and downloaded them successfully (total 264 KB). This confirms that individual file access works fine.

Download stop point: The download always stops at approximately 40 MB, regardless of which folder or subfolder I try to download. The speed drops to 0 KB/s and never recovers.

Browser message: No error message appears in the browser. The download simply freezes at ~40 MB with 0 KB/s speed. I have tested this on both Chrome and Edge browsers.

Small folder test: Yes, I tested this extensively. I tried downloading each subfolder individually (ADL1 through ADL9 in NonFall, and multiple subfolders in Fall). All of them stalled at 0 KB/s and failed. Even the smallest subfolders (e.g., Fall25 with only 732 items) failed to complete.

Summary: Individual JPG files download successfully, but any folder/ZIP download fails at ~40 MB regardless of folder size. The "Sync" button is not visible for external guest users on this shared folder.

Could you please advise how to enable the OneDrive Sync option for external/guest users, or suggest another reliable method to download large datasets from a shared OneDrive folder?

Thank you very much for your support.
Doris V 1,700 Reputation points Microsoft External Staff Moderator

2026-05-28T06:18:08.28+00:00
Dear @ERNIYAZOV SARVARBEK,

Thank you for the detailed testing.

At this point, the only reliable options require action from the UHN researcher or their IT team:

1/ Ask the researcher to reshare via a different platform

The simplest and fastest solution. The researcher can:

Upload the dataset to other service and share a download link with you.

Share the files through Microsoft Teams, which handles large file transfers more reliably for external users.

This requires no IT involvement and can be done immediately.

2/ Ask the researcher to request external sync access from UHN IT

If the researcher asks UHN IT to enable external user syncing for the shared folder, the Sync button will appear for you. You can then use the OneDrive desktop app to sync all files automatically in the background, no ZIP files, no size limit.

Note: This requires a SharePoint admin setting change and may take some time.

For reference: B2B Sync for SharePoint and OneDrive.

I'm sorry for the inconvenience and appreciate your patience.
Doris V 1,700 Reputation points Microsoft External Staff Moderator

2026-05-29T06:25:20.54+00:00

Dear @ERNIYAZOV SARVARBEK,
Is there any update from you? If yes, please feel free to let me know.
ERNIYAZOV SARVARBEK 0 Reputation points

2026-05-30T12:14:57.7533333+00:00

Hello Doris,

Thank you for following up.

I have contacted the data owner / site owner of the external SharePoint folder. They informed me that:

This dataset has been shared with hundreds of researchers for more than 8 years without such download issues.

Due to the size of the dataset and limited resources, they cannot move it to another platform.

From their side, they are not aware of any recent changes in configuration.

On my side, the problem still persists:

Folder downloads from this specific external SharePoint stop at around ~40 MB and the ZIP is corrupted or contains Error.txt.

I have already tried different browsers, OS, networks, and downloading smaller sub‑folders, but the behavior is always the same.

Large downloads from other OneDrive/SharePoint tenants, as well as from other cloud services, work normally on the same machine and network.

Since I am only an external user and cannot access the tenant admin center, is there any further diagnostic step you recommend, or any specific information/logs I can ask the data owner’s Microsoft 365 / SharePoint admin to provide when they open a support ticket with Microsoft?

If the issue is most likely on the hosting tenant side and cannot be solved from my side as an external user, please also feel free to confirm that, so I can inform the data owner accordingly.

Thank you again for your help.