There is more about the problems with the optical scan system used in the Scottish elections. It seems as though the database was problematic. Computerworld reports that
The company has now offered a more detailed explanation of the glitch. A spokesperson said: “The DRS e-counting systems encountered significant fragmentation (up to 99%) of a number of the database indexes which caused the complex queries required to produce final results and some status summary reports to time out.
“Whilst investigations are still under way to understand the precise reason for the index fragmentation, at this early stage it remains likely that the number of rejected ballots was the major contributory factor.”