Firefox uses the Unix Epoch format to store datetime strings, so you need to convert this to the format Excel uses.

See:

• /questions/1335038 Deleting saved logins not used for 5 years
• https://www.google.com/search?sa=N&num=100&q=excel%20convert%20unix%20epoch

Dear Sir or Madam; Thank you for your input. I believe you are correct in the translation of Unix dates to corresponding EXCEL Dates. My problem is that I'm no longer versed in intermediate math. I'm very old. Anyway, My problem became how to translate a UNIX date in scientific format to a number.

Given: 1. The Scientific dates used in the Firefox login/pw table are in UNIX GMT milliseconds.

           2. The offset between UNIX and EXCEL is 70 years.
           3. EXCEL Day 1 is 1900/1/1
           4. UNIX Day 1 is 1970/1/1    (We eventually need to add 70 years to make it an EXCEL date.)

Here's what I finally found:

A2: 1.640552253122E+12 Format: Scientific, 12 zeroes Actual value in excel: 1640552253122

B2: =((((A2/10^3)/60)/60)/24) + DATE(1970,1,1) Format: yyyy/dd/mm hh:mm:ss.000 Actual displayed value in EXCEL is: 2021/12/26 20:57:33.122

I had made the original task/problem more difficult than it had to be. The EPOCH CONVERTER made me realize I had more digits in the actual scientific formatted number. When I changed from 5 to 12 zeroes, I could see them.

See https://www.epochconverter.com

A2: 1.640552253122E+12 Format: Scientific, 12 zeroes Actual value 1640552253122 B2: =((((A2/10^3)/60)/60)/24) + DATE(1970,1,1) Format: yyyy/mm/dd hh:mm:ss.000 Actual value displayed: 2021/12/26 20:57:33.122

Notes: 1. Firefox dates are in UNIX GMT millisecond format. 2. The offset between UNIX GMT Day 1 and EXCEL Day 1 is 70 years. 3. The UNIUX Day 1 is 1970/1/1 and the EXCEL Day 1 is 1900/1/1. 4. An EPOCH CONVERTER at https://www.epochconverter.com was a useful tool.

For now I have to figure out how to highlight the row with the most recent logon date within each group of sites (location URLs where I logged on. There are hundreds of those records. I would like to delete all but the most recent logon record for each site. That would leave me records with the most current site, logon ID and logon password records. I'd keep this current password list on a flash drive off of the PC. Any ideas?

For now I will only by highlighting the 'keepers'.

I added my solution here twice but didn't save it properly. Problem solved.

640552253122E+12 Format: Scientific, 12 zeroes Actual value 1640552253122 B2: =((((A2/10^3)/60)/60)/24) + DATE(1970,1,1) Format: Custom, yyyy/mm/dd hh:mm:ss.000 Actual value displayed: 2021/12/26 20:57:33.122 (GMT)

Notes: 1. Firefox dates are in UNIX GMT millisecond format. 2. The offset between UNIX GMT Day 1 and EXCEL Day 1 is 70 years. 3. The UNIUX Day 1 is 1970/1/1 and the EXCEL Day 1 is 1900/1/1. 4. An EPOCH CONVERTER at https://www.epochconverter.com was a useful tool.

For now I have to figure out how to highlight the row with the most recent logon date within each group of sites (location URLs where I logged on. There are hundreds of those records. I would like to delete all but the most recent logon record for each site. That would leave me records with the most current site, logon ID and logon password records. I'd keep this current password list on a flash drive off of the PC. Any ideas?

For now I will only by highlighting the 'keepers'.

640552253122E+12 Format: Scientific, 12 zeroes Actual value 1640552253122 B2: =((((A2/10^3)/60)/60)/24) + DATE(1970,1,1) Format: Custom, yyyy/mm/dd hh:mm:ss.000 Actual value displayed: 2021/12/26 20:57:33.122 (GMT)

Notes: 1. Firefox dates are in UNIX GMT millisecond format. 2. The offset between UNIX GMT Day 1 and EXCEL Day 1 is 70 years. 3. The UNIUX Day 1 is 1970/1/1 and the EXCEL Day 1 is 1900/1/1. 4. An EPOCH CONVERTER at https://www.epochconverter.com was a useful tool.

For now I have to figure out how to highlight the row with the most recent logon date within each group of sites (location URLs where I logged on. There are hundreds of those records. I would like to delete all but the most recent logon record for each site. That would leave me records with the most current site, logon ID and logon password records. I'd keep this current password list on a flash drive off of the PC. Any ideas?

For now I will only by highlighting the 'keepers'.

Note that you can easily convert an epoch string via a JavaScript bookmarklet in Firefox or via the Web Console. You can create a new bookmark and paste the JavaScript code in its Location field and give it a suitable name.

javascript:void(prompt('datetime',(new Date(Number(prompt('epoch',Date.now())))).toISOString()));

javascript:var d,DT=prompt('paste 13 digit epoch string',Date.now());
if(DT){
d=new Date(Number(DT));
prompt(d.toLocaleString('en-GB')+'\n'+d.toISOString()+'\n'+d.toUTCString(),d.toISOString());
}
void(0);