"That was very bad, I stumbled coming out of the blocks. I'm not very fond of these blocks," he said.
"I think these are the worst ones I've ever experienced. I have to get this start together because I can't keep doing this.
"It's shaky. When I did my warm up it pushed back. It is just not what I am used to. Not as sturdy or firm.
Bolt did enjoy coming back to the stadium where he won his second 100m Olympic title five years ago.
"The crowd is always wonderful," he said. "They always show me so much love and I always appreciate being here.
"I'm excited about getting through to that final and doing my job to my best."
Fellow Jamaican Julian Forte was the fastest qualifier for tomorrow's finals and the only sprinter to go under 10 seconds, clocking a personal best 9.99 sec.
Bolt's long-time rival Justin Gatlin clocked 10.07 sec with the most interesting aspect of his run was the reception he got from the capacity crowd inside the London Olympic Stadium.
When the two-time drug cheat was introduced a chorus of boos rang out and they again started even when he'd crossed the finish line.
Fellow American Christian Coleman, the fastest man in the world this year, took out the opening heat in 10.01 sec.
Another contender Yohan Blake, the 2011 world champion, finished second in his heat in a moderate 10.13 sec.
The race lost one of its major players with the withdrawal of Canada's Andre De Grasse because of a hamstring injury.
In the men's long jump Australia's Fabrice Lapierre, the 2015 silver medallist, just scrapped through qualifying.
The top 12 progress through to the final with Lapierre falling into 12th spot with a best leap of 7.91cm.
It was a lucky escape for the 33-year-old who is determined to make up for last year's disappointing final in Rio where he went in as one of the favourites but could only manage 10th.
"I didn't hit the board on any of my attempts tonight, and if tomorrow I can do that then I'm in the mix for a medal," Lapierre said.
"It was pretty nerve-racking waiting, once I saw Jeff (Henderson, Rio Olympic champion) go up I thought I was no chance but I managed to sneak in. I just can't wait to come back tomorrow. The crowd is awesome."
Fellow Australian Henry Frayne missed qualifying with a best jump of 7.88cm.
In the women's 1500m heats Zoe Buckman was the only Australian to progress through to the semi-finals, clocking 4min05.44sec to finish ninth in the fastest heat.
Melbourne's Georgia Griffith (4:08.99 sec) and Linden Hall (4:10.51 sec) failed to qualify.
Pole vaulter Liz Parnov and discus throwers, Benn Harradine and Mitchell Cooper, also didn't make it through qualifying.
