Hi fthill2003, Let's try this:

On your Win 7 machine, disconnect from Sync first. Then, type about:support in the address bar and press enter. On the Troubleshooting Information page scroll down to the Places Database section and click the Verify Integrity button.

Close the Troubleshooting Information tab and restart Firefox.

Re-connect to Sync and see if your History transfers.

Note that Sync only transfers history of the last two months (60 days) and uploads only history for the last thirty days (not sure about the initial Sync).

Why using Sync if you can also transfer data directly from one profile folder to another profile folder or device using a portable USB drive ?

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

You can copy files like these with Firefox closed to the current profile folder to recover specific data.

• bookmarks and history: places.sqlite
• bookmark backups: compressed .jsonlz4 JSON backups in the bookmarkbackups folder
• cookies.sqlite for the Cookies
• formhistory.sqlite for saved autocomplete Form Data
• logins.json (passwords) and key4.db (58+) or key3.db (57 and older) (decryption key) for Passwords saved in the Password Manager
  if you only have key3.db then make sure to remove an existing key4.db
• cert9.db (58+) or cert8.db (57 and older) for (intermediate) certificates stored in the Certificate Manager
  if you only have cert8.db then make sure to remove an existing cert9.db
• persdict.dat for words you added to the spelling checker dictionary
• permissions.sqlite for Permissions and possibly content-prefs.sqlite for other website specific data (Site Preferences)
• sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder)

Hi. Thanks for your help. I did get sync to transfer browsing history. I had to verify places on both Win 7 and Win 10 machines, and yes, only got part of the history. I had to copy places and favicons from the Win 7 machine and copy to the Win 10 machine to get entire history file. Now, Firefox crashes immediately upon startup, although it will eventually run after several restart/send crash message. But, many websites show only blank pages, and, the big one, the Firefox help page shows 3 big blue circles, a blue X, and a funny black/white world picture, and then text. When i search the help I can't find any mention of this particular issue. so, where do I look for help with that one? it seems profile based because new and default profiles show the help page correctly.

If you have submitted crash reports then please post the IDs of one or more recent crash reports that start with "bp-".

• bp-xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

You can find the report ID of recent crash reports on the "Help -> Troubleshooting Information" (about:support) page.

• click the "All Crash Reports" button on this page to open the about:crashes page and see all crash reports.

Alternatively you can open about:crashes via the location/address bar.

See also:

• https://support.mozilla.org/en-US/kb/Firefox+crashes

Maybe check for these issues on the Windows 10 laptop.

• https://old.reddit.com/r/firefox/comments/f2d5cu/nothing_will_load/

If you have 0patch Agent:

• https://0patch.zendesk.com/hc/en-us/articles/360011227079-Mozilla-Firefox-72-can-crash-upon-launching-when-0patch-Agent-is-installed

Also, see if one of these threads help:

https://support.mozilla.org/en-US/questions/1279587 https://support.mozilla.org/en-US/questions/1279841

Thanks for your help so far. My transferred Firefox profile sometimes works. I have tried "refresh" that does not help, usually makes it worse. Anyway, as cor-el asked, some crash report "bp" numbers below:

bp-336c2cd5-e775-4b9d-8e76-7e9f90200217 bp-455a8c0d-8445-4cc9-a8ab-288760200217 bp-17c9fd8c-4864-4a76-96f4-0e3af0200217 bp-1e5d985c-8927-43f9-b3e4-6a8f90200217 bp-e96a0ec6-410c-432f-a0f3-42dce0200217

Best Rgds

I should add that sometimes shutting down the machine, waiting a minute, and the starting up gets things working again.