DIT Triage - Slow Performance
Symptom: Capture One is running slowly — slow preview generation, laggy interface, long transfer times, or the system feels bogged down.
1. Is the disk nearly full?
Check: Apple Menu > About This Mac > Storage. Or in Finder, click the hard drive and press Cmd+I.
Less than 10 GB free → EC - Disk Full Recovery
Plenty of space → Next.
2. Is Spotlight indexing the capture folder?
Open Activity Monitor (Applications > Utilities). Look for mds_stores or mds using high CPU (>30%).
Yes — Spotlight is indexing every new file as it arrives. Fix: System Settings > Siri & Spotlight > Spotlight Privacy > add the capture folder (drag it in). This stops indexing immediately. The CPU spike should drop within seconds.
No → Next.
3. Is Time Machine backing up the capture folder?
Time Machine triggers a backup whenever new files appear. If it’s backing up to a slow external drive, it competes for disk I/O with Capture One.
Check: Time Machine icon in menu bar > “Backing Up” during the shoot.
Yes — System Settings > Time Machine > Options > Exclude the capture folder. Or: temporarily disable Time Machine during the shoot.
No → Next.
4. Is iCloud syncing the Desktop or Documents folder?
If iCloud Desktop & Documents is enabled, and the capture folder is inside Desktop or Documents, every new RAW file gets queued for iCloud upload. This consumes bandwidth, disk I/O, and CPU.
Check: System Settings > [Your Name] > iCloud > iCloud Drive > “Desktop & Documents Folders” toggle.
If enabled AND capture folder is in Desktop/Documents — Move the capture folder to a location outside Desktop and Documents (e.g., /Users/photographer/Captures/ or an external drive). You can change the capture destination in Capture One without stopping the session.
Not enabled, or capture folder is outside these locations → Next.
5. Is antivirus real-time scanning every file?
Corporate Macs often have antivirus that scans every new file. Known offenders: CrowdStrike Falcon, Malwarebytes, Norton, Sophos, McAfee. Each scan adds 100-500ms per file.
Check: Activity Monitor > look for processes like falcon, MBAMDaemon, NortonAutoProtect, SophosScanD.
Yes — Add the capture folder to the antivirus exclusion list. If you don’t have access to antivirus settings (corporate MDM), this cannot be fixed on set — live with the lag or switch to a non-managed machine.
No → Next.
6. Is the laptop thermally throttling?
Fans running at full speed? Laptop hot to the touch? Has the shoot been running 2+ hours? Is the lid closed (clamshell mode)?
Yes → EC - Thermal Throttling
No → Next.
7. Is an external SSD throttling?
If capturing to an external NVMe SSD in an enclosed case, the SSD may be thermal throttling after sustained writes.
Check: Transfer times progressively increasing, SSD enclosure hot to touch.
Yes → EC - External SSD Failure
No → Next.
8. Are you shooting high-megapixel files?
Phase One IQ4 (150MP), Sony A7R V (61MP), Canon R5 II (45MP), Nikon Z8/Z9 (45MP), Fujifilm GFX (100MP/102MP) — these produce very large RAW files.
Yes — If preview generation is the bottleneck:
- Disable “Auto Adjust” on import if enabled
- Set Focus Mask to off during the shoot
- Consider capturing to fast internal NVMe storage rather than external drive
- If on USB 2.0 cable: switch to USB 3.x cable (transfer speed difference: 480 Mbps vs 5+ Gbps)
No → Next.
9. Are multiple Capture One instances running?
Check Activity Monitor for multiple “Capture One” processes.
Yes — Force quit all but one. This can happen if Capture One crashed and a zombie process remained while a new instance was launched. The zombie process may be holding a file lock on the session database.
No → Next.
10. Nuclear: Nothing specific found but still slow
All diagnostic steps exhausted. Perform a full performance reset:
- Quit all non-essential applications (browsers, email, Slack, Music)
- In Capture One: Edit > Preferences > Performance > check that hardware acceleration is enabled
- Clear the preview cache: Capture One > Preferences > Performance > “Clear Cache”
- Restart Capture One
- If still slow after all the above: restart the laptop. This clears any system-level resource contention.