New version 3005 doesn't open my previous project files on windows 10

[DmitryBarashev]

It seems that you missed one of the updates. You need to do what is written in this topic:

Knowledge Base: if GanttProject 3.+ won't launch after installing a new update

We have a few reports about the issue with launching GP 3.0 where it starts and hangs at the splash image (other symptoms are also possible) Possible reasons and configurations where they are applicable to are listed below. 1. Missing update This applies to GanttProject 3.0.+ on all operating systems. This is not applicable to GanttProject 3.1.+ GanttProject 3.0.+ may fail to launch because of a missing update which was skipped. Unfortunately, due to a bug in the update system, the update whi…