A C: drive rarely fills because of one big file. It is usually a handful of folders that grow quietly: app caches, updates, AI models, build folders and Windows’ own reserved space. The trick is to find what grew, not just what is big.
1. Start with Windows’ own storage page
- Open Settings › System › Storage.
- Wait for the categories to load, then choose “Show more categories”.
- Note the three biggest: usually Apps & features, Temporary files and System & reserved.
- Open Temporary files and clear what you recognise. Leave Downloads unticked unless you have checked it.
2. Turn on Storage Sense
Storage Sense clears temporary files automatically when space runs low. In Settings › System › Storage, switch on Storage Sense and choose how often it runs. It is safe and costs nothing.
3. Look for the usual suspects
- AppData: browsers, chat apps, game launchers and editors keep caches in C:\Users\<you>\AppData. It is hidden by default.
- AI models: Ollama, LM Studio, Hugging Face and ComfyUI each keep model files that are often several gigabytes, sometimes the same model twice.
- Developer folders: node_modules, Rust target, Python virtual environments and Gradle caches pile up next to old projects.
- Windows Update leftovers and the component store (WinSxS).
- The hibernation file (hiberfil.sys) and page file (pagefile.sys).
- Virtual disks for WSL and Docker, which grow but never shrink on their own.
4. Measure folders, not guesses
Windows Explorer does not show folder sizes. A disk analyzer does: it scans the drive and shows the biggest folders first, so you can see in a minute where the space is.
5. Find what grew, not just what is big
A 40 GB game you installed on purpose is not the problem. The problem is the folder that was 2 GB last month and is 30 GB today. To see that you need two scans to compare, a week or a day apart.
→ where Tidemark helps
Where Tidemark helps
- Overview shows each drive’s change this week and alerts when one suddenly fills.
- Apps adds up each app’s space across Program Files, AppData and ProgramData.
- History compares snapshots and pinpoints the folders that grew, with a forecast of when the drive will be full.
- Clean lists what is safe to clear, already ticked, and sends it to the Recycle Bin.
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