What version is being used? What is the length of the project? What is the resolution and size of the bulk of the source files?
Update to the latest. For licensed users upgrades are free for up to six months from purchase date. After that, VP will continue to fully function but a fee will be required in order to register the newest. Retain your old install file and registration info.
Audio may not play until the green caching line above video thumbnails has completed. On lengthy or complex projects this can take some time.
Please share a project that has the issue. It's not difficult, takes little time and can be private. Someone here will be glad to check it out...
1. With your project on the timeline, click on MENU at the top-left. Click FILE|BACK UP PROJECT FILES TO FOLDER. Choose a folder and SELECT FOLDER.
2. Locate the saved, numbered folder, NOT the exported or VPJ file. Upload it to a free server - Google Drive, MS OneDrive, etc.*
3. Get a shared, public link. If using Google Drive click GET SHAREABLE LINK. Change "restricted" to "anyone with the link can view" Then click COPY LINK | DONE.
4. Paste that link here, or click the folder at the top-right of this forum and privately message it to me. It won't be shared.
* Before uploading, right-click the folder, click PROPERTIES. Look at the File Size to confirm that it's not too big for the free space on the server.