One day, I suddenly could not select, cut, or paste at exact times.  For example, if I have set Sonar to select by Measure, when I try to select, cut, or paste at 5:1:0, I might end up with 4:4:113 or 5:1:03 or some other odd value.  The same thing happens with resolution set to quarter, 8th, 16th, etc.  This means I must always do Select by Time or Paste Special to make sure the time is correct.
 
I have checked Preferences and settings repeatedly and see nothing wrong.
 
I seriously doubt the code has changed unexpectedly, so is there a subtle setting somewhere I am missing?  This is a real productivity killer.
 
Thanks.
 

I will try to play around with this a little later in the day - likely 2-3 hours from now, but will see what happens.  I am finishing packing as I am moving today.
 
I DEFINITELY make a lot of timing errors, so time-based positioning for me too is quite important.  I will post back in a bit, and will review anything else folks post in the thread on the matter. 
 
Bob Bone
 

Landmarks enabled?
 
If saving and re-opening the project or restarting SONAR fixes it, I'd say it's likely a bug; otherwise it's probably a setting.
 
I realize it's a pain to stop working in the throes of creativity and troubleshoot, but it would be best if you brought it up at the time it's occurring and capture a video or screenshot of what's happening and how snap is configured.

You've probably checked, but if you're talking audio, make sure Snap to Nearest Audio Zero Crossings is unchecked under Preferences > Customization > Snap to Grid. I think having this checked is the default, so when you upgrade, it gets re-checked. 

Thanks, Craig.  This is MIDI and Audio.  It is like my cursor just won't snap to an "even" time. I will, however, check the setting you recommend.  It would be great if that were the fix.
 
Should I write a big dramatic post like "I've had it with Sonar!!  Going to Studio One!!"   Haha...just kidding.
 
In all seriousness, as you know, I think I have a corrupted install that is not Sonar's fault and I am going to upgrade to the latest and greatest in a few weeks.  Maybe a lot of my weird issues will go away.

I didn't think zero-crossings was a likely suspect because the nearest zero-crossing is usually within a few ticks and wouldn't account for such large errors when snap is at a measure. But I was wondering whether this occurs when selecting in the timeline or only in clips...?

I put the cursor on the timeline and click to mark the start or thru or the paste location.  It appears that the time is always EXACTLY wherever I put the cursor which of course is seldom EXACTLY at a measure or bar, no matter how hard I try.  If you have Measure selected as the resolution/snap, you should be able to drag on the timeline just within a beat or two and get what you want.
 
The odd thing is how it just stopped working one day as though I bumped a keyboard shortcut by mistake.

I am using a newer version of sonar than you are - however - is the "to" and "By" switch in the correct position?

If I didn't know you, Konradh I'd say check the Snap To/By settings or Snap to Landmarks or all the various other wackiness that can happen with Snap.
 
Then again maybe it's just one of those brainfart things and Snap got borked out on ya without you realizing.
 
Complex tool that masquerades as simple but once something gets knocked out of default settings it can really wreak havoc.
 
That would defs be the first place I'd look and I'm sure you already have so this post is probably useless.
 
Cheers.

Beepster
That would defs be the first place I'd look and I'm sure you already have so this post is probably useless.
 

But not to the person who experiences this in the future and remembers what you said.