OneDrive: High SSD I/O Since Mar 2025 Update, mklink /j Junctions Suspected

Bug Report: Suspected NTFS Junction (mklink /j) Interaction Causing Excessive OneDrive SSD Read/Write Activity on My System Since March 2025, Potentially Linked to Recent OneDrive Update

Date: June 2, 2025 Product: Microsoft OneDrive

Operating System:

• Edition: Windows 10 Pro for Workstations
• Version: 22H2
• OS Build: 19045.5917
• Installed on: ‎2024/‎9/‎24
• Experience Pack: Windows Feature Experience Pack 1000.19061.1000.0

Summary: Since approximately March 3rd/4th, 2025, OneDrive has been causing an extremely high and sustained level of read/write activity on my system's SSD. Notably, I have been utilizing the same configuration, including Git repositories within OneDrive and NTFS junction points (mklink /j), since October 2024 without any such issues. This abrupt change in behavior starting March 2025 strongly suggests that a recent OneDrive update may have introduced a regression or altered its handling of these elements on my system, leading to the current problem. This behavior is significantly impacting my SSD's health and potentially my system's performance.

Date First Observed: The issue began noticeably on my system around March 3rd, 2025, with a sharp increase in disk write commands observed from March 4th, 2025, onwards, as evidenced by the "Host Write Commands" graph (see attached picture 1).

Problem Description: On my system, OneDrive.exe consistently exhibits high I/O read and write byte counts, leading to excessive disk activity. This is evident from:

1. The long-term graph of "Host Write Commands" (picture 1), which shows a dramatic and sustained increase starting in early March 2025, rising from approximately 3,500,000,000 to over 12,000,000,000 by late May 2025 on my system.
2. Process monitoring tools (picture 3) show OneDrive.exe with significantly higher "I/O Read Bytes" and "I/O Write Bytes" compared to other active processes on my system. For example, OneDrive.exe shows I/O Read Bytes in the hundreds of millions and I/O Write Bytes in the hundreds of millions, far exceeding other applications.
3. Resource Monitor details (picture 2) confirm OneDrive.exe as the process with high disk activity on my system, specifically reading and writing to its operational database files such as SyncEngineDatabase.db-wal and SyncEngineDatabase.db. The screenshot shows these files located at H:\OneDriveINTEL\OneDrive\Settings\Business1\, which is where I have relocated my OneDrive cache or settings using mklink /j. (It is important to note that this relocation is not believed to be related to the cause of the excessive I/O from OneDrive; rather, I performed this relocation because my primary C: drive was already subject to frequent writes and its lifespan was a concern. The excessive I/O from OneDrive simply followed the cache to its new location on drive H:.)

Potential Contributing Factors to Observed Behavior on My System:

1. Use of NTFS Junction Points (mklink /j): I utilize mklink /j in conjunction with OneDrive. This involves junction points within my OneDrive folder pointing to other locations, and I also used it as a troubleshooting step (relocating OneDrive's cache, as mentioned above). This is a primary suspected trigger for the excessive I/O. (See "Additional Context Regarding mklink /j Usage" below for specifics).
2. Use of Git Repositories: I store and manage Git repositories within OneDrive-synced folders. The frequent small file changes typical of Git operations might be triggering excessive sync activity, possibly exacerbated by the interaction with junctions.

Troubleshooting Steps I Have Already Taken:

1. I identified OneDrive as the primary source of high disk I/O using system monitoring tools.
2. I relocated my OneDrive local cache/settings folder (typically C:\Users\[Username]\AppData\Local\Microsoft\OneDrive) to a different physical drive (Drive H:, path appears to be H:\OneDriveINTEL\) using mklink /j, as detailed in the Problem Description. Despite this relocation, the excessive I/O pattern persists on the drive now hosting these OneDrive operational files.
3. I attempted to reset OneDrive settings and functionality.
4. I performed a full reinstallation of the OneDrive application.
   • Neither resetting nor reinstalling OneDrive resolved the excessive disk I/O issue on my system.
5. I can confirm I have used Git repositories within OneDrive folders and mklink /j for other purposes within my OneDrive setup since October 2024; the problem only manifested in March 2025.

Additional Context Regarding mklink /j Usage: It is important to clarify that my use of NTFS junctions (mklink /j) differs from some scenarios discussed in public forums (e.g., the Microsoft Answers thread at https://answers.microsoft.com/en-us/msoffice/forum/all/solved-onedrive-constantly-writing-to-disk-to-the/68958911-1161-4c5e-b920-dee7e55bc0ac). In my case, the junctions are created between locations that reside ​on the same hard drive​.

For instance, a typical mklink /j command I use creates a junction within one of my OneDrive-synced folder structures that points to another directory also located on the C: drive. An anonymized example reflecting my usage pattern is: mklink /J "C:\Path\To\My_OneDrive_Business_Account\MainSyncFolder\ProjectX_Vault\Subfolder_A\Notes_Junction" "C:\Another\Local_Path_SameDrive\ProjectX_SourceData\RawNotes_Target"

This type of same-drive junction configuration, where the junction link is inside a OneDrive folder and the target is elsewhere on the same drive, was part of my stable setup from October 2024 until the onset of the excessive disk I/O issue in March 2025.

Expected Result: OneDrive should synchronize files and perform background operations with reasonable disk I/O that does not lead to constant, excessive read/write activity, especially when my system is idle or with minor changes. Disk activity should not be at a level that significantly impacts SSD lifespan or system responsiveness, even when NTFS junctions (including same-drive junctions as described) are part of the configuration.

Actual Result: OneDrive is causing continuous and abnormally high SSD read/write operations on my system, as detailed by the attached screenshots. This has been ongoing since early March 2025, and I strongly suspect it to be related to its handling of NTFS junctions as configured on my system.

Impact on My System:

• Potential reduction in SSD lifespan due to excessive writes (this was already a concern for my C: drive, prompting the cache relocation, and is now a concern for drive H: due to OneDrive's behavior).
• Possible degradation of overall system performance and responsiveness.
• Concern over data integrity and system stability.

Attachments:

1. picture 1: Graph from my system showing "Host Write Commands (FF_1250)" over time, illustrating the sharp increase in writes since March 2025.
2. picture 3: Screenshot from a process monitoring tool on my system (similar to Process Explorer) showing high I/O activity for OneDrive.exe.
3. picture 2: Screenshot from Resource Monitor on my system (or similar, in Chinese) showing disk activity by process, with OneDrive.exe prominently active and detailing file access to its database files on drive H:.

Request: I request an investigation into why OneDrive, particularly after a potential update or change around March 2025, began exhibiting this excessive disk I/O behavior on my system. I ask for a strong focus on its interaction with NTFS junctions (mklink /j), especially same-drive junctions as detailed in my "Additional Context" section, and particularly in environments also using Git. This configuration worked without issue for me from October 2024 to early March 2025. Guidance on how to mitigate this issue or information on a forthcoming fix would be greatly appreciated.

Picture 1

Picture 2

Picture 3