The Law was that 1/10th of all land production in a year—grain, fruit, herds, and flocks—were to be devoted to God, as Leviticus 27:30-33 (cf. Deut 14:22) indicates (NKJV):
And all the tithe of the land, whether of the seed of the land or of the fruit of the tree, is the LORD’s. It is holy to the LORD. 31 If a man wants at all to redeem any of his tithes, he shall add one-fifth to it. 32 And concerning the tithe of the herd or the flock, of whatever passes under the rod, the tenth one shall be holy to the LORD. 33 He shall not inquire whether it is good or bad, nor shall he exchange it; and if he exchanges it at all, then both it and the one exchanged for it shall be holy; it shall not be redeemed.’”
This was for the purpose of feeding the Levites, Numbers 18:21,
Behold, I have given the children of Levi all the tithes in Israel as an inheritance in return for the work which they perform, the work of the tabernacle of meeting.
Normally the tithe was to go to the Tabernacle/Temple (Deut 12:5-6), but every third year the tithe was to be stored within the gates of one's own area to service travelling Levites and others in need, per Deut 14:28-29 (cf. 26:12):
28 At the end of every third year you shall bring out the tithe of your produce of that year and store it up within your gates. 29 And the Levite, because he has no portion nor inheritance with you, and the stranger and the fatherless and the widow who are within your gates, may come and eat and be satisfied, that the LORD your God may bless you in all the work of your hand which you do.
In the Second Temple period, Nehemiah worked to restore this (Neh 10:35-38):
35 And we made ordinances to bring the firstfruits of our ground and the firstfruits of all fruit of all trees, year by year, to the house of the LORD; 36 to bring the firstborn of our sons and our cattle, as it is written in the Law, and the firstborn of our herds and our flocks, to the house of our God, to the priests who minister in the house of our God; 37 to bring the firstfruits of our dough, our offerings, the fruit from all kinds of trees, the new wine and oil, to the priests, to the storerooms of the house of our God; and to bring the tithes of our land to the Levites, for the Levites should receive the tithes in all our farming communities. 38 And the priest, the descendant of Aaron, shall be with the Levites when the Levites receive tithes; and the Levites shall bring up a tenth of the tithes to the house of our God, to the rooms of the storehouse.
But when he was away for a time (Neh 13:6), the tithes were neglected (Neh 13:10-13):
10 I also realized that the portions for the Levites had not been given them; for each of the Levites and the singers who did the work had gone back to his field. 11 So I contended with the rulers, and said, “Why is the house of God forsaken?” And I gathered them together and set them in their place. 12 Then all Judah brought the tithe of the grain and the new wine and the oil to the storehouse. 13 And I appointed as treasurers over the storehouse Shelemiah the priest and Zadok the scribe, and of the Levites, Pedaiah; and next to them was Hanan the son of Zaccur, the son of Mattaniah; for they were considered faithful, and their task was to distribute to their brethren.
So there were serious issues during the early years of the Second Temple period in all the people bringing in all the tithes. Whether some people were fully tithing and some were not tithing at all, or some doing only part of a tithe, it is not clear. But what is clear is that all the tithes (the totality of the 1/10ths that were to have been given by all people of Israel) were not coming in again during Malachi's time. The use of "all" in the passage does indicate that some tithing was being done, but partial obedience (whether individually or corporately with only part of Israel obeying) was not obedience at all. So to get God's blessing in Mal 3:10, full—individual and corporate—obedience was needed.