又用英文关键词“firefox can’t clear form and search history”搜了一下,还真找到了答案。
Q:why won’t firefox clear my search and form history? it’s greyed out whenever i try to clear it.i am not in private browsing mode and still can’t clear this history
A possible cause is a problem with the file search.sqlite that stores the search history。
Rename or delete formhistory.sqlite (plus formhistory.sqlite-journal and formhistory.sqlite.corrupt and formhistory.dat, if they exist) in the Profile Folder in case there is a problem with the file that stores the “Saved Form” data. This will remove all saved form data, so you may want to rename formhistory.sqlite to formhistory.sqlite.sav or move the file to another folder in case you need to recover some saved data.
Help > Troubleshooting Information > Profile Directory > Open Containing folder