"Reading Block" takes much time when loading

Hi, I opened the Wave module, and use “external: SWAN”. After run SWAN and EFDC, I close the software. However, when I re-open this project, I find that it is very slow for EE to read the project. It will fail to respond when “Reading Block: XX” (Fig1), and I wait about 10 minutes for EE to finally load it. Could you tell me what the “Reading Block” mean? And I open this model in a “one-year” time. I plan to run a verification period with two years, so I am afraid if EE will fail to read the project then (with opening time of 2*10min = 20 min)?