severe lag scrubbing premiere 26
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ADOBE PREMIERE PRO 26.0.2 — BUG REPORT
Scrubbing lag caused by progressive session-state degradation — page fault storm on memory-mapped proxy files
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DATE: 2026-03-31
SYSTEM SPECIFICATIONS
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OS: Windows 11 Pro 25H2 (Build 26200)
CPU: Intel Core i9-14900K (24 cores / 32 threads)
RAM: 32 GB DDR5 — 2x 16 GB Corsair @ 4800 MHz (XMP: 7000 MHz)
GPU: NVIDIA GeForce RTX 3090 — Driver 559.97
System SSD: WD Black SN770 1TB NVMe (C: drive, OS + Media Cache)
Proxy SSD: Samsung 990 PRO 4TB NVMe (G: drive, proxy files)
Media Cache: C:\Users\Owner\AppData\Roaming\Adobe\Common
PREMIERE PRO CONFIGURATION
--------------------------
Version: 26.0.2
Playback Engine: Mercury Playback Engine GPU Accelerated (CUDA)
Source media: Offline (proxies only workflow)
Proxy codec: Apple ProRes 422 Proxy (apco)
Proxy resolution: 1920x1080
Proxy frame rate: 29.97 fps
PROXY FILE DETAILS (ffprobe — all 26 files)
--------------------------------------------
All files share the following codec properties (consistent across all 26):
Container: QuickTime MOV
Video codec: Apple ProRes 422 Proxy
Codec tag: apco
Resolution: 1920x1080
Frame rate: 29.97 fps (30000/1001)
Pixel format: yuv422p10le (4:2:2, 10-bit)
Bit depth: 10 bits per raw sample
Color space: BT.709
Color transfer: BT.709
Color primaries: BT.709
Color range: TV (limited)
Field order: Progressive
Audio codec: PCM signed 16-bit little-endian (sowt)
Audio rate: 48000 Hz stereo
Encoder tag: Apple ProRes 422 Proxy
File Duration Video Bitrate File Size
---------------------------------------- ---------- ------------- ---------
P1001731_Proxy.mov 178.19 min 42,901 kbps 59.39 GB
P1070048_Proxy.mov 158.07 min 40,799 kbps 50.19 GB
P1090155_Proxy.mov 159.20 min 40,306 kbps 49.96 GB
P1020523_Proxy.mov 159.39 min 38,407 kbps 47.75 GB
P1010447_Proxy.mov 153.60 min 38,481 kbps 46.10 GB
1_yi4k_1_1_20251116_123109_Proxy.mov 172.32 min 33,285 kbps 45.01 GB
1_yi4k_2_1_20251116_123109_Proxy.mov 171.67 min 31,865 kbps 43.01 GB
1_yi4k_3_1_20251116_123109_Proxy.mov 171.14 min 30,892 kbps 41.63 GB
P1010448_Proxy.mov 23.77 min 44,207 kbps 8.16 GB
P1090156_Proxy.mov 18.08 min 45,001 kbps 6.31 GB
DJI_20251115205002_0003_D_Proxy.mov 24.96 min 42,291 kbps 8.21 GB
DJI_20251115213758_0005_D_Proxy.mov 24.96 min 42,150 kbps 8.18 GB
DJI_20251115213957_0005_D_Proxy.mov 24.96 min 42,118 kbps 8.17 GB
DJI_20251115222952_0007_D_Proxy.mov 21.74 min 43,927 kbps 7.41 GB
DJI_20251115220455_0006_D_Proxy.mov 24.96 min 38,096 kbps 7.42 GB
DJI_20251115222754_0007_D_Proxy.mov 21.62 min 43,092 kbps 7.24 GB
DJI_20251115220256_0006_D_Proxy.mov 24.96 min 36,660 kbps 7.15 GB
DJI_20251115211301_0004_D_Proxy.mov 24.96 min 35,480 kbps 6.93 GB
DJI_20251115202504_0002_D_Proxy.mov 24.96 min 35,345 kbps 6.91 GB
DJI_20251115211459_0004_D_Proxy.mov 24.96 min 34,514 kbps 6.75 GB
DJI_20251115202305_0002_D_Proxy.mov 24.96 min 34,506 kbps 6.75 GB
DJI_20251115200008_0001_D_Proxy.mov 24.96 min 28,932 kbps 5.71 GB
DJI_20251115195809_0001_D_Proxy.mov 24.96 min 30,070 kbps 5.92 GB
DJI_20251115204803_0003_D_Proxy.mov 24.96 min 40,847 kbps 7.94 GB
P1020524_Proxy.mov 13.15 min 44,444 kbps 4.54 GB
P1070049_Proxy.mov 12.88 min 44,599 kbps 4.46 GB
ISSUE DESCRIPTION
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After opening a project and editing for several minutes, scrubbing becomes
severely laggy (effectively unusable). The lag is not tied to any specific
clip, file, or timeline position — it can occur anywhere in the timeline.
It is progressive: performance degrades the further into the editing
session the user works, and is consistently worse when working past the
1-hour mark of a long timeline.
Critically: closing and reopening the project (without restarting Premiere)
fully resolves the lag. The previously laggy section scrubs smoothly again.
However, after a few more minutes of continued editing further along the
timeline, the lag returns again at the new working position.
This rules out the source files or specific clips as the cause. The issue
is entirely session-state dependent — it accumulates as the user edits
through the timeline and resets when the project is closed and reopened.
Playback (linear forward playback) is unaffected throughout. The issue is
exclusively triggered by scrubbing (random seek / click-to-position).
NOTE: Premiere Pro does not provide a live "free memory" button. The
available cache management options (Edit > Preferences > Media Cache >
Delete, or Clear Media Cache Files at launch) address stored media cache
on disk, not live session memory. There is no in-app way to release
accumulated session memory without closing the project or restarting
Premiere.
STEPS TO REPRODUCE
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1. Open a project containing a long sequence (1+ hour timeline) using
ProRes Proxy files
2. Begin editing — scrub, trim, apply effects — working progressively
through the timeline
3. After several minutes of editing, scrubbing becomes laggy
4. Lag worsens the further into the timeline the user works
5. Close the project (File > Close Project) and reopen it
6. The previously laggy position now scrubs smoothly
7. Continue editing forward — lag returns within a few minutes at the
new working position
EXPECTED: Consistent scrubbing performance throughout a session
ACTUAL: Progressive degradation of scrubbing performance correlated
with session duration and timeline position; only resolved by
closing and reopening the project
DIAGNOSTIC DATA — PAGE FAULT ANALYSIS
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Monitoring was performed using Windows Performance Counters during active
lag. All measurements taken with NVIDIA RTX 3090 GPU acceleration active.
State | Premiere RAM | Free RAM | Page Faults/sec
-----------------------------|--------------|----------|----------------
Premiere open, no project | 1.6 GB | 16.8 GB | 0
Project open, before scrub | 3.5 GB | ~16 GB | 0
After light scrubbing | 6.0 GB | ~14 GB | 0
LAGGING (scrubbing) | 4.5 GB | 13.4 GB | 44,000 - 46,930
Key observations:
- CPU usage during lag: 5-10% (not CPU bound)
- Disk I/O during lag: ~0% (not disk bound)
- Free RAM during lag: 13+ GB (not RAM exhausted)
- Page faults are bursty: spike to 46,000+/sec then drop to near 0
- Faults are predominantly soft page faults (no corresponding disk I/O)
ROOT CAUSE ANALYSIS:
The issue is a progressive degradation of Premiere's internal session
state during editing. As the user scrubs and edits through a long
timeline, Premiere accumulates memory mappings, frame cache entries,
and/or handle state that is not released during the session.
Measured at the point of lag: Premiere generates 44,000–46,930 soft
page faults per second when scrubbing. CPU is 5-10%, disk I/O is ~0%,
and 13+ GB of system RAM is free — confirming this is not a hardware
resource exhaustion issue but an internal memory management problem
within Premiere's session state.
Premiere memory-maps proxy files for read access. As the user progresses
through the timeline over a session, the accumulated page table footprint
across memory-mapped files appears to grow until seek operations trigger
massive soft page fault bursts. Closing and reopening the project resets
this state entirely, confirming the cause is within the session lifecycle.
ATTACHED FILES
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1. Windows Performance Recorder (WPR) trace captured during active lag:
Temppremiere_lag2.etl
Trace profile: GeneralProfile
Dropped events: 0
2. Premiere Pro project file:
20251115 <my file>.prproj
3. Open file handle snapshot at moment of lag (Sysinternals handle.exe):
handles_lagging.txt
4. Open file handle snapshot after scrubbing (before lag):
handles_after_scrub.txt
5. Open file handle snapshot baseline (project open, before scrubbing):
handles_project_open.txt
6. Screen recording captured simultaneously with the WPR trace:
20260331_201303_Adobe_Premiere_Pro_mkHUOocs28.mp4
Start time: 2026-03-31 20:13:03
Duration: 83.7 seconds (1 min 24 sec)
Size: 29.1 MB
The screen recording visually shows the scrubbing lag occurring in
real time and is time-synchronized with the WPR trace. Engineers can
correlate the visible lag moments in the video with the page fault
spikes in the ETL trace using Windows Performance Analyzer (WPA).
WORKAROUNDS (partial)
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1. Close project and reopen to temporarily reset session state
FEATURE REQUEST:
Premiere Pro currently has no way to release accumulated session memory
without closing the project or restarting the application. A live
"Free Memory" or "Clear Session Cache" option (similar to After Effects'
Edit > Purge > All Memory & Disk Cache) would provide a critical
workaround for users hitting this issue.
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Files are available at
https://drive.google.com/drive/folders/1lDHNqmXxmILJaxJ880MyfkhiFn4Qz8Md?usp=sharing
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