My windows XP VM, under PD 11 in macOS v10.11.6, had been working perfectly well for a long time until I updated it to the last version 11.2.1(32626). here is the error I 've met, which makes my windows XP VM as a disaster: I 've always got an error while installing the latest parallels tools at 62%. I check the log files and see an INSTALLMESSAGE_ERROR: Failed to install driverprl_mouf . I don't know what happened, only this error makes the installation has to roll back and uninstall my PD drivers which makes VM very hard to use. please give me a hand or tell me how to roll back my PD 11 version to 11.2.0? Thanks I just uploaded the log file as attachment. Thanks again.