I created a redaction mark on some text and then applied redaction. It worked fine for me. I used Windows 7 64 bit machine. If the workflow that you are doing is different from what I did, then please give the detailed steps.
Also, please try creating a simple pdf file containing only text and check if the redaction is getting applied. If the redaction is getting applied successfully in it, then please share a pdf file in which applying redactions freezes Acrobat.
I have had the same problem with Acrobat XI, I keep on hoping that it will be fixed on the next update but no such luck. Every single time I mark for redaction and then Apply Redactions I get a MS dialog box saying Adobe Acrobat has stopped working.
Running Acrobat XI Pro v.11.0.08
Windows 8.1 64bit
Acrobat just updated, must have been just to fix this issue because the version hasn't even changed and the problem is now fixed!
Acrobat DC still freezes when trying to apply the redaction of a single sentence (single text string). The number of pages with this string is about 1400 pages. Acrobat will start to apply the redactions, then after a while, shows "(Not Responding)" at the top of the window. The process of applying redactions ceases because Acrobat is no longer swapping to scratch files on the disk.
I am using Windows 10 Pro on an HP ZBook (server notebook) with 16GB of memory. My Hard drives are less than half full.
There are no updates to apply and this is a persistent Acrobat problem.