Summary
Bug Report – UEFN / Sequencer → Size reported as 1 GB in Cinematic Device
Product: UEFN (Unreal Editor for Fortnite)
UEFN Version: [e.g., 30.20]
Platform: [Windows 10/11]
Project ID: [project name]
Date: [DD/MM/YYYY]
Description
Since the last update, a Level Sequence of approximately 1 minute created with Sequencer displays a normal size (~130 KB in the Content Drawer).
However, as soon as I assign this sequence to a Cinematic Device in the scene and launch a session (Playtest), UEFN tells me that the Sequence “weighs” 1 GB. This problem did not exist before the update.
This is therefore a regression: the same sequence/project did not cause this problem before.
Steps to Reproduce
Create a Level Sequence in UEFN (duration ≈ 1:00).
Save it; its size displayed in the Content Drawer is ~130 KB.
Place a Cinematic Device in the scene.
Assign the Level Sequence to the Cinematic Device.
Launch a session (Playtest).
Observe the warning/message indicating that the Sequence is ~1 GB.
Expected Result
The size of the Level Sequence must remain consistent (a few hundred KB) and not be overestimated to 1 GB when launching the session via the Cinematic Device.
Observed Result
When launching the session, UEFN reports that the sequence is ~1 GB, which:
is inconsistent with the actual size (~130 KB),
may block or slow down the session launch,
did not occur before the last update.
Frequency
Always (100%) on my project since the update.
Additional Details
The Level Sequence does not contain large assets (no heavy external audio/video).
The problem only occurs once assigned to the Cinematic Device and in session.
Before the update [number/specify previous version if known], the same setup worked without this size increase.
What I’ve already tried
Rebuild/Resave the sequence.
Delete/re-add the Cinematic Device.
Restart UEFN / machine.
New test project with a simple sequence → same symptom.
Empty DerivedDataCache / Saved (optional, if you have done so).
Suggested Attachments
Screenshot of the Content Drawer showing the size ~130 KB.
Screenshot of the in-session message indicating ~1 GB.
Excerpt from the logs (Saved/Logs) covering the session launch.
System information (CPU, RAM, GPU, drivers).
Thank you in advance for your help! Don’t hesitate to contact us if you need a minimal reproducible project.
Please select what you are reporting on:
Unreal Editor for Fortnite
What Type of Bug are you experiencing?
Memory
Steps to Reproduce
Create a Level Sequence in UEFN (duration ≈ 1:00).
Save it; its size displayed in the Content Drawer is ~130 KB.
Place a Cinematic Device in the scene.
Assign the Level Sequence to the Cinematic Device.
Start a session (Playtest).
Observe the warning/message indicating that the Sequence is ~1 GB.
Expected Result
The size of the Level Sequence must remain consistent (a few hundred KB) and not be overestimated to 1 GB when launching the session via the Cinematic Device.
Observed Result
When launching the session, UEFN reports that the sequence is ~1 GB, which:
is inconsistent with the actual size (~130 KB),
may block or slow down the session launch,
did not occur before the last update.
Platform(s)
pc