Symptoms

FlexiCapture SDK throws the error:

Unable to access Project ('C:\TestFolder\Project\Project.fcproj.sync').
This object is locked by user USERNAME on computer COMPUTERNAME.

Cause

Multiple threads are trying to access the same project resources. The exact number of threads is hard to predict: "C:\ProgramData\ABBYY\FCSDK\12\FlexiCapture SDK\Samples\C#\ParallelProcessing" sample would throw the same error in the case of parallel workers' number equal to 30.

FlexiCapture SDK doesn't control critical sections and simultaneous access to the same project's resources by different processes. It should be taken into consideration during development.

Resolution

1. Use synchronization programming tools to make sure the opening/adding image/batch/closing are not done simultaneously: critical sections/restart on exception/etc;
2. Create project's copy + set a different temp folder for each process.