Thank you for your question.
I am sorry you are having a problem with the chainsaw. If the chain is coming off the problem is the chain is not properly tensioned. I recommend checking the condition of the chain and bar first. Then look at the gear to be sure it is not worn. It ant of the arts are worn they should be replaced. Then put the chain and bar on the saw. Once you have the chain tensioned carefully turn the chain by hand, to be sure it does not loosen up. If it is fine, tighten the bar nut and check the operation. When running the saw, you will need to tension the chain as it wears.
I hope this is helpful. Please let me know if you need further assistance.
If you do not feel confident repairing this problem yourself, then you can have it repaired by a Sears technician. Here is a link that will provide the nearest drop-off locations:
Sears Home Services
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