Security Will NOT Update in Price History

I suggest you restore a recent datafile backup that does not have the issue. If you haven't already, you may wnt to review:

t I manually track. Quicken dropped all price histories for the manually e ntered daily price prior to 17 May 2018.

a NEW price for dates prior. In the price history update, I can type in th e new data for a previous date, but it does not stick. When I go to the po rtfolio view and go to a date prior to 17 May, they are blank. When I atte mpt to fill a price for that date, again it does not save/take.

SP funds that I track this way, but not having a problem with them.

Also, you can import security prices from a CSV file (see Quicken Help for how to do that). And since my ex-wife was also invested in various TSP sec urities ... I'm pretty sure that they can download prices in a CSV format.

NOTE, however, that the downloaded CSV format might not precisely match Q's requirement ... so you might have to play around with the CSV file in a sp readsheet program to get it to work. Just be sure to save the file back to CSV format.