Error planning calculation : unplanned work

Ok. I understand that I cannot bypass it.
Therefore, is there a way to know how to unblock this situation (I just know that these meetings are problematic) or to organize more efficiently my projects so that this kind of situation works ?

Typically, I organized in various projects my activities which correspond to different charges.
I created some project templates containing milestones, activities and meetings (by the way, I have to set a fake date to the meetings) which enable to plan efficiently new projects.
I have ~10 parallel projects in parallel with ~ 10% assigned to me each.
I imagine that a full day meeting in a project where I am assigned 10% worries the planner ?

Thanks for your quick answer.

Just to be sure I set the right parameters at the right place:

- in the resource page, I set every project rate at 100% even if it worries Projeqtor that the total amount of affectations is over 100%
- in the assignation of each task I put the real rate, say 10%

?