Instructions to resolve Company Of Heroes 2 Sync-Error for Proton (Tested on 5.0-10)

proton_compat_coh2_syncerror.md

Instructions to resolve Company Of Heroes 2 Sync-Error for Proton (Tested on 5.0-10 and 6.3-2)

In support of this comment on Proton's CoH2 issues thread: Company of Heroes 2 (231430) #3875

Based on original solution by @Cytomax55 in the same thread.

Instructions for workaround

1. Uninstall/delete CoH2:

   • (1a) Uninstall CoH 2 on steam.
   • (1b) Delete remaining files here: rm -rf "~/.steam/steam/steamapps/common/Company of Heroes 2"
   • (1c) Delete compatibility data for CoH2: rm -rf ~/.steam/steam/steamapps/compatdata/231430/

2. Clear download cache in Steam -> settings -> "downloads" tab (requires Steam login afterwards; ⚠️make sure you know your Steam credentials beforehand!⚠️.

3. Reinstall CoH2 on Steam.

4. Launch CoH 2 -> at this stage game would still give 'Sync Error' in multiplayer games either immediately after loading the map or when first enemy is encountered with proton 5.0-10, 5.13-6, 6.3-6, experimental, 6.14-GE-2.

5. Download vc_redist.x64.exe at ✅https://www.microsoft.com/en-us/download/details.aspx?id=48145 from the microsoft website. Note that another link, namely ❌https://aka.ms/vs/16/release/vc_redist.x64.exe did NOT WORK, as it was missing the required DLL at the time this report was submitted.

6. make separate directory to extract vc_redist.x64.exe to. E.g. mkdir /tmp/vcredist && cp /PATH/TO/DOWNLOAD/vc_redist.x64.exe /tmp/vcredist/vc_redist.x64.exe.

7. cd to the download directory and extract vc_redist.x64.exe using cabextract to the directory you chose as such: cabextract vc_redist.x64.exe -d /tmp/vcredist. If this did not result in ucrtbase.dll being extracted, use cabextract again to extract a10 specifically.

8. Copy or move ONLY ucrtbase.dll to ~/.steam/steam/steamapps/compatdata/231430/pfx/drive_c/windows/system32/ (cp /tmp/vcredist/ucrtbase.dll ~/.steam/steam/steamapps/compatdata/231430/pfx/drive_c/windows/system32/) . May require sudo privileges.

9. Launch Company of Heroes 2 in Steam using Proton 5.0-10. I have only played 1 match, but given that the sync-error would occur immediately or on the first enemy sighting before, I suspect this resolved the sync-error issue. Not yet tested on 6.3-2.

Note: tested on Steam native client, Manjaro w/ kernel 5.10.59

Info on system used for testing

3950x @ stock GTX 1080 @ stock 64GB (16x4) DDR4 @3200MHz Asus X570-E Strix

Processor Information:

CPU Vendor: AuthenticAMD

CPU Brand: AMD Ryzen 9 3950X 16-Core Processor

CPU Family: 0x17 CPU

Model: 0x71

CPU Stepping: 0x0

CPU Type: 0x0

Speed: 6336 Mhz 32 logical processors

16 physical processors

HyperThreading: Supported

Operating System Version:

"Manjaro Linux" (64 bit)

Kernel Name: Linux

Kernel Version: 5.10.59-1-MANJARO

X Server Vendor: The X.Org Foundation X Server

Release: 12013000

X Window Manager: KWin

Steam Runtime Version: steam-runtime_0.20210630.0

Video Card:

Driver: NVIDIA Corporation NVIDIA GeForce GTX 1080/PCIe/SSE2

Driver Version: 4.6.0 NVIDIA 470.63.01 OpenGL

Version: 4.6 Desktop Color Depth: 24 bits per pixel Monitor

Refresh Rate: 144 Hz

VendorID: 0x10de

DeviceID: 0x1b80 Revision Not Detected

Number of Monitors: 4

Number of Logical Video Cards: 1 Primary Display

Resolution: 2560 x 1440

Desktop Resolution: 8079 x 1440

Primary Display Size: 23.50" x 13.23" (26.97" diag) 59.7cm x 33.6cm (68.5cm diag)

Primary Bus: PCI Express 16x Primary

VRAM: 8192 MB

Supported MSAA Modes: 2x 4x 8x 16x

Sound card:

Audio device: Nvidia GPU 83 HDMI/DP

Memory:

RAM: 64290 MB

Miscellaneous:

UI Language: English

LANG: en_US.UTF-8

Total Hard Disk Space Available: 272831 Mb

Largest Free Hard Diskn Block: 25106 Mb

Storage:

Number of SSDs: 4

Number of HDDs: 6