Starting a scan
SizeTrend can scan a complete local drive or one folder. Whole-drive scans can use fast filesystem metadata access on NTFS, FAT32, and exFAT, while folder and non-elevated scans still have a regular Windows fallback.
Open the Scan menu. Connected drives appear under Drives, and recently scanned folders appear near the bottom. Click Select folder... when the location is not already listed.
The drive list refreshes when Windows reports that removable storage was connected or removed. It also refreshes when you open the Scan menu, which helps if a device notification was missed.
Scan the whole drive when you do not yet know where the space went. That gives the Overview pane enough context to find large applications, system storage, cleanup opportunities, and automatic What Changed history.
Choose one folder when the question is already narrow, such as a project, shared data folder, or user profile. A folder scan is quicker to review, but it cannot explain storage elsewhere on the drive and is not eligible for every whole-drive Overview feature.
For a complete NTFS, FAT32, or exFAT drive, SizeTrend can read filesystem metadata directly. Windows requires administrator privileges for that read-only volume access. The prompt can restart SizeTrend as administrator and reopen the requested drive.
You can check Always start SizeTrend as administrator if that matches how you use the program. Choosing No keeps SizeTrend open and uses the regular Windows folder enumerator instead. The fallback is slower and may be unable to read some protected locations, but it does not require elevation.
FAT32 and exFAT are common on USB flash drives, memory cards, and portable disks. Select the drive the same way you select an NTFS volume. A direct metadata scan is available for a complete local FAT32 or exFAT drive when SizeTrend is running as administrator.
Do not disconnect the device while it is being scanned. If the drive disappears or changes during the metadata read, SizeTrend reports the affected location rather than treating a partial result as a complete scan.
If Windows reports that the selected drive is locked, SizeTrend opens the native Windows BitLocker unlock dialog when possible. Enter the password or recovery information there, then return to SizeTrend and click Retry after Windows can open the drive.
SizeTrend does not receive or store the BitLocker password or recovery key. If Windows cannot open the unlock dialog, File Explorer is opened so you can unlock or make the drive accessible there.
Check that the device is connected, has a drive letter, and opens in File Explorer. A drive can also become unavailable because it is sleeping, disconnected, locked again, or failing. Retry only after Windows can read it normally.
For an ordinary folder, verify that your Windows account can open it. Administrator access can help with protected local folders, but it does not grant access to data owned by another account or repair filesystem damage.
Start broad when the cause is unknown.
A complete drive scan gives SizeTrend the context it needs to explain the storage.