I've a Husqvarna 445e with tool less chain tensioner. Couple of months ago I thought the chain was stretching and had to stop frequently to re-tension.
Changed chain, sprocket which was worn and checked bar was getting oiled OK.
Having marked the position it is the bar which is in fact slipping back. You use the 'knob' to tighten the bar and however hard I tighten, it always slips back within a couple of minutes of use.
Anyone had and solved this problem please?