Hi Fulvio Valente,
Here are some checkpoints to check.
1. Check if you have multiple MSOffice installed.. We have seen this type of issues when customer have mixed office installation with some parts of office 2010 and some parts of office 2013. This is not supported by Microsoft also. You can check this in your Control Panel->Add/remove program. When SAPGUI start up it loads in office dll's like ACECORE.dll. Issue can happen when there are multiple installations. Try cleaning up all office products and reinstalling.
2. A corrupted History db/tab chain also can do this. Try switching off tabchain(note 2244786) and switching off history in the sapgui options dialog and check this issue. This is also something that gets loaded when connection is made.
3. If the above both points do not help then the only way to figure out what is happening is taking a crash dump of the issue as per note 1387962- Analyzing crashing SAP Logon/SAPGUI process and opening an incident with SAPGUI support.
Regards,
Geetha.