After several successful creations the audio is not syncing correctly. After bringing in a clip the audio is fine. After splitting the and deleting the unwanted portion the sync is lost. Is there a fix?
This happens a lot to files recorded with a variable frame rate. Such as from game play recordings or some smartphones / cameras capable of recording in H265 (HEVC). Either set the camera / screen recorder to record at a constant frame rate or convert your files first to a constant frame rate with HandBrake.
If the video is from and iPhone, or other mobile device, then this is most likely caused by the video being Variable Frame Rate (VFR)
Download and install MediaInfo and analyse one of the clips causing the issue , see this tutorial on how to setup MediaInfo and analyse a video clip for all the data required.
In the video section of the analysis if you see:
Frame rate mode: Variable
The video needs converting to Constant frame rate (CFR) using a video converter such as Handbrake or Avidemux
Do note - if the video is VFR and the frame rate difference between the Minimum and Maximum is more than 3 - 4 fps then conversion to CFR may not fully fix the issue with the sync and you may also experience judder on pans or where there is fast movement acrooss the scene when exporting. This is not a fault of the program, it is due to the the VFR of the video.
If the video is VFR then post the MediaInfo analysis and the specification of your computer system including Windows version and program version, see this topic for what is required and please quote processor and graphics card make/model in full, and also what monitor/screen resolution(s) you are working with if this is a laptop.
I would suggest you out the system specification in your profile signature, in your profile signature.
Please do as @johnebaker asked and download and install MediaInfo. Then point it at one of your files which "works" and one which does not. Post the results of both files here.
It is very difficult for fellow-users to help you since we do not have all the necessary information and, obviously, we cannot see your computer screen!
(BTW, your "Signature" is intended to be used to show the details of your computer hardware and software. Then, users who wish to help you do not need to ask for such details; they will automatically show with any post you make.)