When processing a product twice (e.g. with different settings) and overwriting the result from the first run leads to two opened products in SNAP. The old instance should have been closed and only the new result should be opened. Not only that this is confusing it can cause several issues with wrong or missing references to the data on disk.
This was initially observed in the issue
The following solutions are conceivable:
The SNAP GUI user is informed that a product with this name and the same file location is already opened in SNAP. If the user agrees to recalculate the product, the product must be closed in SNAP, all references must be released, including those held by virtual bands (e.g. RGB view), all associated files must be deleted and only then the product can be processed.
If one of the actions fails, so that the deletion of the files is not completely possible, an error message must appear and the recalculation must be prevented.
The SNAP GUI user is requested to enter a different file name for the product to be recalculated.