I got the same issue. Following is my log:
X 05:07:55,171 S050931 ~Thr: Exception during save overwrite or rename (last success: ChecksumVerified): C:\users\crossover\AppData\Roaming\Captain of Industry\Saves\Untamed Archipelago\25-07-09_05-07-54_4144-autosave.save
---> IOException: 成功。 : 'C:\users\crossover\AppData\Roaming\Captain of Industry\Saves\Untamed Archipelago\25-07-09_05-07-54_4144-autosave.save'
at System.IO.FileSystem.DeleteFile (System.String fullPath) [0x0001a]
at System.IO.File.Delete (System.String path) [0x00014]
at Mafi.Core.FileSystemHelper.DeleteFile (System.String filePath) [0x00078]
at Mafi.Core.SaveGame.ASyncSaver.doWork (System.Object _, System.ComponentModel.DoWorkEventArgs __) [0x00174]
X 05:07:55,270 S050933 ~Mai: Exception when checking file size.
---> IOException: Unknown error (0x17700c0) : 'C:\users\crossover\AppData\Roaming\Captain of Industry\Saves\Untamed Archipelago\25-07-09_05-07-54_4144-autosave.save'
at System.IO.FileSystemInfo.EnsureDataInitialized () [0x00034]
at System.IO.FileSystemInfo.get_Attributes () [0x00000]
at System.IO.FileInfo.get_Length () [0x00000]
at Mafi.Core.SaveGame.SaveManager.sync () [0x00081]
G 05:08:42,515 S051872 ~Sim: Research done
G 05:13:36,213 S057745 ~Sim: Goal completed
G 05:14:02,785 S058273 ~Sim: Research done
G 05:14:09,180 S058400 ~Sim: Goal completed
I 05:21:58,669 S061681 ~Mai: GameSaver: Saving took 161 ms
W 05:21:58,671 S061681 ~Thr: Save tmp file already exists, deleting.
at Mafi.Core.SaveGame.ASyncSaver.doWork (System.Object _, System.ComponentModel.DoWorkEventArgs __) [0x00000]
at System.ComponentModel.BackgroundWorker.OnDoWork (System.ComponentModel.DoWorkEventArgs e) [0x00000]
at System.ComponentModel.BackgroundWorker.WorkerThreadStart (System.Object argument) [0x00000]
at System.ComponentModel.BackgroundWorker.<RunWorkerAsync>b__27_0 (System.Object arg) [0x00000]
at System.Threading.Tasks.Task.InnerInvoke () [0x00000]
at System.Threading.Tasks.Task.Execute () [0x00000]
at System.Threading.Tasks.Task.ExecutionContextCallback (System.Object obj) [0x00000]
at System.Threading.ExecutionContext.RunInternal (System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, System.Object state, System.Boolean preserveSyncCtx) [0x00000]
at System.Threading.ExecutionContext.Run (System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, System.Object state, System.Boolean preserveSyncCtx) [0x00000]
at System.Threading.Tasks.Task.ExecuteWithThreadLocal (System.Threading.Tasks.Task& currentTaskSlot) [0x00000]
W 05:21:58,673 S061681 ~Thr: Failed to delete tmp save file, continuing.
at Mafi.Core.SaveGame.ASyncSaver.doWork (System.Object _, System.ComponentModel.DoWorkEventArgs __) [0x00000]
at System.ComponentModel.BackgroundWorker.OnDoWork (System.ComponentModel.DoWorkEventArgs e) [0x00000]
at System.ComponentModel.BackgroundWorker.WorkerThreadStart (System.Object argument) [0x00000]
at System.ComponentModel.BackgroundWorker.<RunWorkerAsync>b__27_0 (System.Object arg) [0x00000]
at System.Threading.Tasks.Task.InnerInvoke () [0x00000]
at System.Threading.Tasks.Task.Execute () [0x00000]
at System.Threading.Tasks.Task.ExecutionContextCallback (System.Object obj) [0x00000]
at System.Threading.ExecutionContext.RunInternal (System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, System.Object
state, System.Boolean preserveSyncCtx) [0x00000]
at System.Threading.ExecutionContext.Run (System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, System.Object state, System.Boolean preserveSyncCtx) [0x00000]
at System.Threading.Tasks.Task.ExecuteWithThreadLocal (System.Threading.Tasks.Task& currentTaskSlot) [0x00000]
I 05:21:59,017 S061681 ~Thr: GameSaver: Save finalize took 341 ms
X 05:21:59,034 S061681 ~Thr: Exception during save overwrite or rename (last success: ChecksumVerified): C:\users\crossover\AppData\Roaming\Captain of Industry\Saves\Untamed Archipelago\1.save
---> IOException: 成功。 : 'C:\users\crossover\AppData\Roaming\Captain of Industry\Saves\Untamed Archipelago\1.save'
at System.IO.FileSystem.DeleteFile (System.String fullPath) [0x0001a]
at System.IO.File.Delete (System.String path) [0x00014]
at Mafi.Core.FileSystemHelper.DeleteFile (System.String filePath) [0x00078]
at Mafi.Core.SaveGame.ASyncSaver.doWork (System.Object _, System.ComponentModel.DoWorkEventArgs __) [0x00174]
X 05:21:59,109 S061681 ~Mai: Exception when checking file size.
---> IOException: Unknown error (0x17700c0) : 'C:\users\crossover\AppData\Roaming\Captain of Industry\Saves\Untamed Archipelago\1.save'
at System.IO.FileSystemInfo.EnsureDataInitialized () [0x00034]
at System.IO.FileSystemInfo.get_Attributes () [0x00000]
at System.IO.FileInfo.get_Length () [0x00000]
at Mafi.Core.SaveGame.SaveManager.sync () [0x00081]