They did also have viruses, but they were usually funny and harmless.
However, business wasn't using IBM PCs in the UK at the time. They didn't get a look in - pretty much everyone was Acorn in the UK.
My father was the FIRST major PC clone importer/builder in the UK (waaaay before Dell even got going here) and he nearly died from lack of sales a couple of times as people were either quite happy with their ancient Acorn kit or bought new Archs when they came out. The PCs of the day were a bag of shite, unreliable and unproductive and people knew it. He now sells Dell kit which is a bag of shite, unreliable and unproductive. How times change....
Unfortunately for Acorn, the tables turned as RM PLC got into the government and promoted the PC, businesses hit the Internet, Windows 3.1 came out with Winsock, Netware was usable and interoperability with the US was required regularly (which was PC all over).
Game over. Momentum destroys superiority.
As for popularity outside the UK, NL, DE and NZ had a fair amount.
One of the great advantages of the Acorn hardware was that there was no barrier to entry if you wanted to program them. Perhaps because their initial focus was computers for use in education everything you needed was always right there. You could sit down and start typing code.
If you wanted to write C (there was a C++ compiler based on CFront too IIRC) then you had to buy a compiler, but people achieved a huge amount with the tools available on stock machines.
For a number of years, Acorn had the most powerful desktop computers in the world at a reasonable price, but they failed to capitalise on that advantage & were eventually overtaken by the MS/IBM/Intel juggernaut.
From what I remember no crashes, viruses or anything of the sort on any of them.
I remember at the time the pressure on the school at the time to switch to IBM PCs "because that is what business is using", which in hindsight feels like a shame.
Were these things popular outside of the UK?