jomi_ta:Once somevody do a project the file extension is .stx. Is it the only one or there is other extension. Please take into consideration that I am a new Sudio12 user and I dont know much about video.
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is .stx. Is it the only one
Yes.
When you Open a New Project, Edit & then Save it, the Studio generated Files relating to your Project are stored in a Grey Project Folder, which can only be Opened by the .stx File with the same Project File Name as the Project Folder, to prevent you from tampering with the Folder's contents.
Go to: My Documents / Pinnacle Studio / My Projects Folder / Open that & you'll see the Grey Folder & .stx File.
TIP - Instead of "Saving" your Edits, do a "Save As", for each one. Same Project File Name, but with incremental Numbers. EG; Video 1.stx, Video 2.stx etc. That way, if you lose your Project for some reason, you can Open the previous one & just Re-Edit that, instead of having to Re-Edit the whole of your Project, from the beginning.