I have deleted and recreated a search application in sharepoint 2013 about 5 times now and every time it gets created with Searchable items All Errors and degraded partitions. What is going on??
Helped me: run PowerShell script, then re-create Search service application:
psconfig.exe -cmd helpcollections -installall -cmd secureresources -cmd services -install -cmd installfeatures -cmd applicationcontent -install -cmd upgrade -inplace b2b -force -wait
Or you can try index reset + full crawl of all my content sources, but this method did not help me, however, everyone recommends it.