May one undo a storage room of non-Muktzah items?
It is forbidden to undo a storage room on Shabbos, as doing so involves a great amount of energy, [and is thus not befitting to the day of rest]. This applies even if the items in the storage room are not Muktzah.
Undoing the storage for the sake of a Mitzvah?
It is permitted for one to undo the storage for the sake of a Mitzvah even if doing so involves much toil. This includes if one needs to use the space of the storage for:
- Using the area as a Beis Midrash.
- Host a Seudas Mitzvah.
- Hosting a meal for guests. Nevertheless it is only considered a Seudas Mitzvah if the guests are from out of town, whether they are sleeping and eating by him, or sleeping elsewhere and only eating by him. If however the guests are from the same city then hosting them is not considered a Seudas Mitzvah but rather a Seudas Reshus and one thus may not empty the storage for their behalf. If however these in town guests were invited in honor of an out of town guest which is staying by the host, then he too is considered like an out of town guest and may have the storage undone on his behalf.
How to undo the storage room, when needed for the sake of a Mitzvah:
Take as much as possible at a time: One is to carry as many items as possible when undoing the storage room in order to lessen the amount of times he will need to go back and forth.
How many people are to empty the storage: Each person may only carry the amount needed for a single person to sit in the area of the storage room. Hence if space is needed for many people each person is to carry out their own area of storage needed to be cleared.
Not to empty the entire storage:  Even if all the space in the storage room is needed, one is not to empty the entire room [if the floor is made of earth] due to worry that one may come to smoothen the ground. [If however the floor is tiled it is allowed to empty the entire storage if needed.]