pboard quit unexpectedly - Copy/Paste broken in High Sierra

I have installed every operating system point release upgrade for years, including the current macOS 10.13.3, and have never encountered any issue with NSPasteboard quitting. This suggests to me that you, and the others reporting this issue have installed something, perhaps innocently, that is causing this issue, and may not be an Apple issue.

Let's start with Flash. Occasionally, there are fake Flash pop-ups that tell you to update your version of Flash, but in reality are front-ends for malware. If you did not purposely get Flash from the official Adobe Flash site, then you may have been invaded. In any event, it might be indicated to run Malwarebytes to see if it finds anything, and offers to remove it. It is a free, 14-day trial, and I personally use it, without compensation for its recommendation.

What applications have you installed just prior to the NSPasteboard failing issues? What applications or drivers are out of date for High Sierra? Are you using a potentially incompatible third-party clip-board manager? Any anti-virus, or so-called Mac cleaner/deep configuration products that can be causing collateral damage?

If you were to boot into Safe Mode, do the NSPasteboard messages persist, or stop occurring?

If so far, nothing seems to resolve this, I also recommend downloading, running EtreCheck, and posting the results here. It will protect your privacy. Again, I use this tool, as do many others here in the communities, and receive no compensation for its recommendation either.

Some details may help. What are you trying to copy and from what app, and where are you trying to paste and into what?

Encrypted disks and Flash have nothing to do with copying and pasting unless you are trying to copy and paste Flash content.

This situation "pboard quit unexpectedly" happens to me daily. I click report to Apple every time.

I'm unable to find the answer?