Is there a limit on number of emission files that CMAQv5.3.1 can open?

Does CMAQ have a limit on the number of (emissions) files that it can open during simulations? When I let 15 gridded 2D emissions file be read individually in the run script via GR_EMIS_XXX environment variable, I got this error towards the end of the second day’s simulation:

However, when I use SMOKE command mrggrid to merge 14 2D sectors into one and read only rwc sector separately, I do not get this error.

Upgrade to a more-recent I/O API and re-build: the max number of files was increased to 256 last October. See

Thanks a lot for helping me out!