Install on macOS Sierra fails “Session UUID file exists”

Wireshark installed once; then, once I removed it, the installation appears to complete but really doesn't:

Feb 23 11:30:38 wahoo installd[303]: PackageKit: ----- Begin install -----
Feb 23 11:30:38 wahoo installd[303]: PackageKit: Session UUID file exists - will not overwrite /var/folders/zz/zyxvpxvq6csfxvn_n0000000000000/C/PKInstallSandboxManager/5CE691EA-4E77-4D41-B64B-E5A20ACD779C.activeSandbox
Feb 23 11:30:40 wahoo installd[303]: PackageKit: ----- End install -----

This shows up in the Installer log no matter which version I try to install. Help!