A hidden Windows 11 file has been quietly filling your drive, and Microsoft never told you

Published Sep 3, 2026, 1:30 PM EDT Abhinav pivoted from a career in banking to pursue his first love in writing. Even while working full-time, he continued contributing as an editor-at-large, a role he has held for more than 7 years. A lifelong tech enthusiast who has built three gaming and productivity powerhouse PCs since 2018, his passion for technology keeps him closely following the semiconductor industry, from NVIDIA and AMD to ARM. His MSc dissertation explored how artificial intelligence will reshape the future of work, reflecting his curiosity about the wider social impact of emerging technologies. There are many things wrong with Microsoft Windows 11, and it's not even news anymore. Users have had to endure broken features, a confused user interface, botched updates, senseless bloatware, and a relentless push for AI features that no one ever asked for. Surprisingly enough, Microsoft continues to expand upon that list, giving more to talk about every time Patch Tuesday comes around. One of the more recent issues involved a single system file swelling without warning, which happened to swallow tens or sometimes almost hundreds of gigabytes on OS drives. Microsoft recently shipped a fix, but if you have delayed or deferred system updates out of skepticism like thousands of other users, there is one particular update that might be worth watching out for. A Windows service was consuming hundreds of gigabytes CapabilityAccessManager took up a huge chunk of storage for many users The culprit was CapabilityAccessManager.db-wal, which is a system file located in the Windows folder, on the user's ProgramData folder, which happens to be hidden by default. As the name suggests, this belongs to Capability Access Manager, the Windows service responsible for governing which apps can reach your camera, microphone, location, and screen capture. Every time an app requested one of those permissions, the service recorded the event in a small SQLite database. The .db-wal file happens to be that database's write-ahead log, which is a holding area for changes that hadn't been merged back into the main file. Now, under normal conditions, the log stays just over a few megabytes, but a bug in Windows 11 24H2 and 25H2 prevented it from being merged back into the main database, so it grew indefinitely as new permission events were recorded. As first reported by Windows Latest, Windows also hid the culprit by listing the missing space as anonymous system storage, which made the problem stubbornly hard for even seasoned users to diagnose. You can check whether your PC is affected in about a minute The diagnosis is fairly straightforward It's not recommended to go looking for the file directly, because it's rather tedious to find, and on the chance that you do find it, you can find that it's protected by Windows, which the OS will just refuse to show. To check if your PC has been affected, you'd have to go into Settings, then System, and then click on "Show more categories". Here, you need to look at the "System & reserved" files figure, followed by the "System files" subcategory. On a normal installation, this should be anywhere around 20–40 GB. That usually indicates that there's no issue. On my own system, I found the file to be about 29.3 GB in size, which indicates the issue has been resolved. If, however, this figure reads in tens or perhaps hundreds of gigabytes above that (as multiple users reported seeing well above 200 GB), your PC could potentially be affected by the permission log issue. There's also a second check worth running, which concerns the OS version your PC is running. Press Windows and R together, type "winver" in Run, and hit Enter. A patched machine will report build 26100.8875 on 24H2 or 26200.8875 on 25H2. Anything below that means the fix has not landed on your device yet. You can't delete the file easily, but you can fix the issue If you installed the update, you should be in the clear Windows shipped a fix on July 14, as a part of the Patch Tuesday cumulative update. The particular update that resolves the issue was KB5101650, and it arrived on all supported Windows 11 systems automatically. However, anyone who has paused updates or just not restarted in a while may still be on an unpatched build without realizing it. As such, it's worth going through all the recently installed updates through Windows Update, resume updates if they were paused, and install the KB5101650 or newer if available. Microsoft themselves noted that the patch improved disk space usage for the CapabilityAccessManager.db-wal file. So, when applied correctly, it should prevent the system file from ballooning to unimaginable sizes. It's worth noting that, while the patch seems to fix the issue, Microsoft has not explained the underlying root cause that stopped Windows from clearing the log in the first place, so not much is known about it in the current analyst discourse. Regardless, the fix seems to be a simple update that should solve it for most users on various Windows 11 devices, hopefully for good. Using Windows 11 feels like a chore, but it's worth checking up on your PC Lately, using Windows 11 has required a lot of housekeeping and due-diligence as a user, and not doing so has arrived with real costs, be it performance, storage space, or perhaps even a combination of two. As such, it's worth running a system-wide audit every once in a while and keeping yourself up-to-date with the developments on user forums to avoid disappointment later.