This message was created because Mechanical uses a significance level of 0.0 for CQC and ROSE combinations. This can result in thousands of post1 combinations because every modal cross term is included. The APDL default is 0.001 and could be specified by a commands object like CQC,0.001.  With this setting the combination may not take too long even with >> 100 modes. I'm familiar with the 80% requirement, but I wonder if it's really necessary if "missing mass" is used to capture the unextracted modes.
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