Symptom: After using the Erase All Data button in the Settings, the labels are missing from the left-hand menu.
Troubleshooting: Some of the database files may be missing. Check in C:\ProgramData\Wasp Barcode Technologies\MobileAssetWeb\Database for a file named CleanCustomMetadata_AC. Note that C:\ProgramData is a hidden folder, so you will need to either set the Windows option to Show Hidden Files and Folders, or just copy and paste the above path into the address line of your File Explorer window.
If that file is missing, download and extract this file into that folder, then reset your data again: