The patch installer has encountered an error.

[Ryu1178]

Update disclaimer

• Yes, I have checked and my issue is not related to the game updating and plugins not working correctly.

What did you do?

Hi there,

This only started once the FFXIV 7.4 version went live.

When attempting to login after entering the OTP, it attempts patching. This then fails with the following:

"_XIVLauncher Error

The patch installer has encountered an error.
Please report this error.

Please try again or use the official launcher_"

We've tried a few things to resolve this:

• Reinstalled XIVLauncher, along with deleting the AppData and LocalAppData folders for XIVLauncher.
• Reinstalled FFXIV.
• Attempted to repair files through XIVLauncher (This also fails)
• Checked Security permissions for the file that is causing the error.
• Using a VPN.

It's worth noting, that the game runs completely fine Vanilla through normal means.

Platform

Windows

Wine/Proton runner version

No response

Relevant log output

2025-12-24 17:03:03.442 +01:00 [INF] [PATCHER] sent hello
2025-12-24 17:03:21.677 +01:00 [INF] [SHMEMRPC] IPC(2): {"$type":"XIVLauncher.Common.PatcherIpc.PatcherIpcEnvelope, XIVLauncher.Common, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null","OpCode":2,"Data":{"$type":"XIVLauncher.Common.PatcherIpc.PatcherIpcStartInstall, XIVLauncher.Common, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null","PatchFile":"C:\\Users\\admin\\AppData\\Roaming\\XIVLauncher\\patches\\game\\ex3\\859d0e24\\D2025.11.26.0000.0001.patch","Repo":4,"VersionId":"2025.11.26.0000.0001","GameDirectory":"D:\\Steam\\steamapps\\common\\FINAL FANTASY XIV Online","KeepPatch":false}}
2025-12-24 17:03:22.616 +01:00 [INF] [PATCHER] Installing C:\Users\admin\AppData\Roaming\XIVLauncher\patches\game\ex3\859d0e24\D2025.11.26.0000.0001.patch to D:\Steam\steamapps\common\FINAL FANTASY XIV Online\game
2025-12-24 17:03:25.471 +01:00 [ERR] [PATCHER] Patch install failed
System.IO.IOException: Errore nei dati (controllo di ridondanza ciclico). : 'D:\Steam\steamapps\common\FINAL FANTASY XIV Online\game\sqpack\ex3\020301.win32.dat1'.
   at System.IO.Strategies.OSFileStreamStrategy.Write(ReadOnlySpan`1 buffer)
   at System.IO.Strategies.OSFileStreamStrategy.Write(Byte[] buffer, Int32 offset, Int32 count)
   at System.IO.Strategies.BufferedFileStreamStrategy.Flush(Boolean flushToDisk)
   at XIVLauncher.Common.Patching.ZiPatch.Util.SqexFileStreamStore.Dispose()
   at XIVLauncher.Common.Patching.RemotePatchInstaller.InstallPatch(String patchPath, String gamePath)
   at XIVLauncher.Common.Patching.RemotePatchInstaller.RunInstallQueue()
2025-12-24 17:03:56.185 +01:00 [INF] Exited due to failure
2025-12-24 17:06:00.963 +01:00 [INF] [PATCHER] IPC connected
2025-12-24 17:06:01.023 +01:00 [INF] [PATCHER] sent hello
2025-12-24 17:06:02.413 +01:00 [INF] [SHMEMRPC] IPC(2): {"$type":"XIVLauncher.Common.PatcherIpc.PatcherIpcEnvelope, XIVLauncher.Common, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null","OpCode":2,"Data":{"$type":"XIVLauncher.Common.PatcherIpc.PatcherIpcStartInstall, XIVLauncher.Common, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null","PatchFile":"C:\\Users\\admin\\AppData\\Roaming\\XIVLauncher\\patches\\game\\ex3\\859d0e24\\D2025.11.26.0000.0001.patch","Repo":4,"VersionId":"2025.11.26.0000.0001","GameDirectory":"D:\\Steam\\steamapps\\common\\FINAL FANTASY XIV Online","KeepPatch":false}}
2025-12-24 17:06:03.036 +01:00 [INF] [PATCHER] Installing C:\Users\admin\AppData\Roaming\XIVLauncher\patches\game\ex3\859d0e24\D2025.11.26.0000.0001.patch to D:\Steam\steamapps\common\FINAL FANTASY XIV Online\game
2025-12-24 17:06:04.902 +01:00 [ERR] [PATCHER] Patch install failed
System.IO.IOException: Errore nei dati (controllo di ridondanza ciclico). : 'D:\Steam\steamapps\common\FINAL FANTASY XIV Online\game\sqpack\ex3\020301.win32.dat1'.
   at System.IO.Strategies.OSFileStreamStrategy.Write(ReadOnlySpan`1 buffer)
   at System.IO.Strategies.OSFileStreamStrategy.Write(Byte[] buffer, Int32 offset, Int32 count)
   at System.IO.Strategies.BufferedFileStreamStrategy.Flush(Boolean flushToDisk)
   at XIVLauncher.Common.Patching.ZiPatch.Util.SqexFileStreamStore.Dispose()
   at XIVLauncher.Common.Patching.RemotePatchInstaller.InstallPatch(String patchPath, String gamePath)
   at XIVLauncher.Common.Patching.RemotePatchInstaller.RunInstallQueue()