KB10747 - When using the Editor to generate a shapefile topology project, the topology building operation is very slow. What might be the problem?

Check to see if anti-virus software is running in the background on your computer. The topology checking/building operation creates a number of special files to which data is repeatedly written during the course of the operation. If the anti-virus software is checking each write-to-file operation, this can slow down the speed of the topology building operation by a factor of 10 times or more.

Try temporarily disabling the anti-virus software while the topology build is being performed.