Our Work

FolderSight: Folder Sizes in Windows Explorer

Windows Explorer shows how big a file is, but never how big a folder is. Finding out means right-clicking, opening Properties and waiting. FolderSight is a Windows tool Kevin built for his own daily work: hover over any folder and a small panel shows its size, counting up live as the folder is scanned, with its file count, its share of the drive and the largest files inside.

• Windows 10 and 11
• C# and .NET
• Explorer extension
• In daily use since January 2026

What Made It Hard

• Explorer waits for no one. Windows gives a tooltip one chance to answer, on the same thread that draws every Explorer window, so a slow answer freezes Explorer. FolderSight's live panel answers right away, then scans on a thread of its own and updates ten times a second.
• A crash takes Explorer down with it. Extensions run inside Explorer itself, so one unhandled error closes the taskbar and every open folder. Every entry point is guarded, so protected system folders, paths that are too long and files that disappear mid-scan never crash Explorer, and folders it cannot read are counted and shown in the panel.
• Settings without reinstalling. Changing a normal Explorer extension means reinstalling it and restarting Explorer. FolderSight rereads its settings within about 30 seconds, so the display style, skipped folders and time limits change on the fly.
• Installs that check themselves. An extension that is registered wrong simply never appears, with no error. The installer checks afterwards that Windows has the extension registered and says so if it doesn't, so a problem shows up at install time instead of as a tool that silently does nothing.

What That Means for Your Project

Most businesses will never need an Explorer extension. The habits that make this one dependable are the ones we bring to a booking system or a customer portal: it stays responsive while it works, it handles the messy cases instead of crashing, settings change without a reinstall, and every release is tested and written down.

Built as a fixed-price project, a tool like this would typically run $8,000 to $17,000. FolderSight's source code is private for now; we're happy to walk through it on a call.