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FAQ

Find answers to common questions about running the Sync-in server and desktop application.

Server​

Why does Sync-in fail to start in a Proxmox VM with a sharp or Unsupported CPU error?​

Symptom. This issue can affect Docker installations running in an AMD64 virtual machine hosted by Proxmox. The Sync-in container keeps restarting and its logs contain the following error:

Unsupported CPU: Prebuilt binaries for Linux x64 require v2 microarchitecture

Cause. Starting with Sync-in 2.4, the prebuilt Linux x64 binaries used by sharp require an x86-64-v2-compatible CPU. A generic CPU model configured in Proxmox may not expose the required instruction set to the virtual machine, even when the physical CPU supports it. When the log contains the error above, reinstalling sharp inside the container is not the appropriate fix.

Resolution. Expose a compatible CPU model to the virtual machine:

  1. Stop the virtual machine.
  2. In the Proxmox interface, open VM → Hardware → Processors → Edit.
  3. Set Type to one of the following values:
    • host: recommended when the VM remains on the same Proxmox host. It exposes the host CPU capabilities directly.
    • x86-64-v2-AES: use this baseline when live-migration compatibility is required. Every possible destination node must support this CPU model.
  4. Start the virtual machine again. A full VM restart is required for the new CPU model to take effect.

Verification. From the Sync-in Docker Compose directory, start the services and inspect their logs:

docker compose up -d
docker compose logs

The container should now start without the Unsupported CPU error.

warning

The host CPU type exposes CPU features specific to the current Proxmox node and may limit live migration to nodes using compatible processors. Use x86-64-v2-AES when a common CPU baseline is needed across a cluster.

If the issue persists. Make sure the VM was fully stopped and started, verify that the CPU change is no longer marked as pending in Proxmox, and confirm that the physical CPU supports x86-64-v2.

Desktop app​

How can I launch the desktop application in hidden mode?​

Use either of the following methods.

Command-line option:

./Sync-in-Desktop.exe --hidden

Environment variable:

SYNC_IN_HIDDEN=1 ./Sync-in-Desktop-1.2.9-arm64.AppImage

Hidden mode can also be enabled from the application settings.

How can I fix the Using GTK 2/3 and GTK 4 in the same process is not supported error?​

Symptom. This error may appear when the desktop application starts on Linux.

Resolution. Restart the application and force it to use GTK 3:

./Sync-in-Desktop.AppImage --gtk-version=3