Did you try to do a restart of pc, if yes and still no startup, i would suggest to reinstall x5.

Hello,
I am sorry about the issue.
I would recommend doing as Andre has suggested, and specifically for the reinstall I recommend these steps below.
The folders to be deleted with these steps usually do not contain any projects, that by default are stored at C:\Users\YourUsername\Documents\Incomedia\WebSite X5 - Pro, but you can check their contents to make sure of this.

1) Uninstall the software normally, from the Windows panel.
2) Go to the path C:\Users\YourUserName\AppData\Local\Incomedia and delete the folder corresponding to your version of the software (it should be WebSite X5 – Pro).
3) Go to the path C:\Program Files and, if it is present, delete the folder corresponding to your version of the software (it should be WebSite X5 – Pro)
4) Do the same at the path C:\Users\YourUsername\AppData\Local\Programs, deleting the folder WebSite X5 – Pro if present.
5) Restart the PC.
6) With VPN (if you use one), antivirus and firewall temporarily disabled, run as admin the installer you can find here: https://www.websitex5.com/download/v2025.2/wsx5_pro.exe

I remain available.