Export file does not match my original editing

I am currently editing a video using one source file (a movie .mkv)

In the editing in Shortcut, everything is finished and cut at the right time and moment. It does lag and slow down during transitions, but that is probably my laptop.

However, when I export the file, all my editing changes. The first cut is different, transitions come in slower or sudden images appear where I never even used them.

For example, this is where I cut in shortcut:

but in the exported file (using vlc) it cuts maybe half a second earlier… (i can only upload one picture as a new user)

This happens a bunch of times throughout the exported file (the audio is fine while I use VLC, but when I open it in wmc, it speeds up. In windows media player, it pays the same as in VLC.

I have used these export settings:

h;264 High profile
codec libx264 - quality based, quality 100 % - GOP 13 - B Frames 2

Anyone who can help me? Or is my project lost? If you need other information or screenshots, just ask me. I really hope I can save it since it took me quite some time. (If necessary, I can start again, since I know where to cut in the original file, but then I really want the guarantee that the export file will be as I edit it in shortcut)

thanks in advance

If it works in the media player and in VLC, isn’t the issue just in the Windows media center? The lag you’re experiencing might have some unintended effects on the video you’re working with. For example, precision can be hard to achieve if your program lags. In order to counteract this you can work in the playlist instead of the timeline, which saves a lot of processing power for your computer. In order to translate your current project back over to the playlist just drag the clips from the timeline. The cuts and filters applied should remain the same, but you might have to re apply transitions manually (Use the fade in, fade out filters.)

As a final thing before you export, I would check your video properties and make sure everything looks normal, such as playback speed and resolution/aspect ratio. I hope this helps.