I know this response is way to late. But I found the solution was simple, just delete any imported 1099's and enter in the whole numbers manually. When you import them TT records every single individual transaction and their backend servers can not handle it. But if you just manually enter the sum total whole numbers for Short Term, Long Term, etc there back end servers will stop crashing.
If you trade a lot like me, or even a few hundred trades will break their back end servers, this has been a problem for me for many many years and now I trade a lot more and it become impossible to use. TT support never figured it out and believe me I spent many weeks on the phone.... But I am a computer person and finally decided even though they won't admit it, there servers can not handle that many transactions, so you just enter in the sum totals and TT online will work just fine. Even their non-online product can handle importing 1099's with a lot of transactions.
So I have changed over to just doing in manually it is not that bad, only four sets of data for each 1099, plus the interest and dividend data and done.
