Introduction
A user complained that his Windows 11 PC became so slow, it became impossible to do any work. A quick look revealed that the hard disk was churning nonstop. After resource monitor finally launched, we noted the hard disk performance:
- 100% utilization
- 1MB/s
Given that normal hard disks can move data at around 200MB/s, this was indeed glacial. It was also hard to ignore the incredible number of Windows processes reading and writing the hard disk:
- backgroundTaskHost.exe
- compattelrunner.exe
- TiWorker.exe
- Windows Module Installer Service
- Windows Store
- System Restore
- Volume Shadow Copy
- MoUsoCoreWorker.exe
- wuaucltcore.exe
- WindowsPackageManagerServer.exe
- MicrosoftEdgeUpdate.exe
- MsMpEng.exe
It was hard to ignore the constant disk chatter, wondering if the heads were about to drop off. Concern only grew when the hard disk reported a temperature of 50°C. What was preventing these processes from completing their reads and writes?
- An infection, with the concomitant hard disk fever?
- A failing hard disk?
- A Windows bug?
A particular path soon began to make its appearance felt with regularity: C:\windows.old\WINDOWS\SysWOW64\config\systemprofile\AppData\Local\Microsoft\Windows\INetCache\IE. Surely C:\windows.old should be of no interest to any programs? What is in the IE directory?
Windows made strenuous effect to resist our investigation of the IE directory:
- Varied file ownership
- Access controls that impedes even Administrators
- Hidden directories
Eventually we reached the IE directory. dir slowly listed the contents:
- Most of the files were small .HTM files of around 1kB
- The filenames used the characters 0 to 9, and A to Z, which implies cache files
- The length of the file name was 8 characters
- Number of file names: potentially
It became evident why the disk was churning:
- Since we eventually liberated 30GB of hard disk space, we can estimate the number of files in the IE directory: files.
- Listing, or traversing the IE directory with millions of files was slow
- Many Windows programs were traversing the huge directory:
- Windows Defender
- Volume shadow copy
- System Restore
- Compatibility scanner
- With Windows doing its own thing, there is nothing left for the user.
Epilogue
It took two weeks to delete the junk. The user reports that the PC is now normal. The hard disk LED blinks occasionally.
