There are two major threats to complex MCMC estimations:

• Wrong energy settings (hibernate after 2 hours of inactivity)
• Automatic Updates (install updates at 3 a.m.)

I thought about the latter threat. At times, you may hand some R code to other co-workers, especially when you need to estimate lots of different models in a short period of time. If they have auto-updates enabled, your results are quickly in jeopardy. While automatically saving the workspace [if(rep==10000) save.image(“save.RData”)] is definitely a very good idea, deactivating automatic updates on windows is still important for long-term calculations.
Therefore I thought about ways to deactivate automatic updates from within R. A major obstacle is UAC (user account control) which turns your administrator account into something … with less right. Windows frequently asks for privilege elevation. Sadly, elevation does not work without further administrative tools, which you will not find on every PC around. Therefore I decided to use the “runas” command, which will ask the user for her password once.
Although this is not a perfect solution yet, it is also a very nice example on some interesting functions: paste, sub, system.

[EDIT]
“runas” apparently does not work with “net stop” command, therefore a .bat file needs to be created which can be started using runas. The .bat is created from within R.

[EDIT2]
Random John reminded my that an option to turn auto update back on would be nice. Well, I added that.