https://community.blueprism.com/t5/Product-Forum/Mainframe-Attach-after-Process-kill/m-p/50957#M6105 Killing an application should always be the very last course of action, you should always build in a clean close/exit in the same way that manual users do.  For some applications or interfaces killing an application can cause locking or api issues.   It sounds like your application has this issue, probably killing the app is impacting the Hllapi interface that Blue Prism is trying to use - I suggest building a clean exit routing/object that keeps pressing whatever the exit keys are for that mainframe (usually a mixture of F3s and/or F12s in my experience - but could be anything, ask an SME), and cleanly exit.   Fri, 16 Feb 2018 14:17:00 GMT Denis__Dennehy 2018-02-16T14:17:00Z https://community.blueprism.com/t5/Product-Forum/Mainframe-Attach-after-Process-kill/m-p/50956#M6104 Hi,   I am restarting Mainframe after using the kill process "Kill pcsws.exe". The whole thing worked fine till now. I am observing a new issue with mainframe attach. the BP fails to attach to proper instance (however it says that  it has attached to existing session only). As a result, BP fails to read screens or match the screen or detect anything else on the screen. Any advices please? Thu, 15 Feb 2018 17:00:00 GMT https://community.blueprism.com/t5/Product-Forum/Mainframe-Attach-after-Process-kill/m-p/50956#M6104 Anonymous 2018-02-15T17:00:00Z https://community.blueprism.com/t5/Product-Forum/Mainframe-Attach-after-Process-kill/m-p/50957#M6105 Killing an application should always be the very last course of action, you should always build in a clean close/exit in the same way that manual users do.  For some applications or interfaces killing an application can cause locking or api issues.   It sounds like your application has this issue, probably killing the app is impacting the Hllapi interface that Blue Prism is trying to use - I suggest building a clean exit routing/object that keeps pressing whatever the exit keys are for that mainframe (usually a mixture of F3s and/or F12s in my experience - but could be anything, ask an SME), and cleanly exit.   Fri, 16 Feb 2018 14:17:00 GMT https://community.blueprism.com/t5/Product-Forum/Mainframe-Attach-after-Process-kill/m-p/50957#M6105 Denis__Dennehy 2018-02-16T14:17:00Z