How to fill missing enteries in column A, and add respective corresponding enteries to column-B with value of previous cell I am facing an issue with an excel file. I have an excel sheet with 2 columns 

Column A :  Time Increment with per second

Column B :  A particular value of a machine sensor 

The problem i am facing is when the machine is stopped (not in motion), the depth increment stop for that particular time and do not make entries in the excel sheet, and once the machine start moving it again add the entries for the starting point. Let me explain in better way as below.

04:23:12    2709.082597
04:23:13    2708.747333
04:23:14    2708.442548
04:23:15    2708.229198
**04:23:16  2708.229198
04:24:01    2708.137763**
04:24:02    2707.924413


The machine is stopped at 04:23:16  and it resumed its activity at 04:24:01 with a gap of 44 seconds.So the excel sheet missed the time entries for those 44 seconds. There are more than 1000 entries like this in the file. What i want that Column A (Time) should be incremented from Cell A  to Cell Z, without missing any entry of the second (even when the machine is stopped), and corresponding value at column B should be added to all 44 cells which should be the value of sensor corresponding to the time 04:23:16 (when the machine stopped) i.e 2708.229198.

Like for example the machine is stopped at 04:23:16, Sensor value at Column B is 2708.229198, i want that file should fill all the missing entries for the time between 04:23:16 to 04:24:01 (44 seconds), and for all those 44 seconds the value at Column B should be 2708.229198 (A value of column B corresponding to 04:23:16), and this can be done for the whole sheet. As i explained its a very lengthy file and to do the option manually is not suitable, that may take hours or even days, I want some practical solution to sort out this issue.

Any help or guidance will be appreciated in this regard.

Jawad
try to make a sheet derived from the source. first, put all possible time in the new sheet in an ordered way. second, do vlookup from source for value. third, put vlookup inside a iferror to find missing value and for second part of iferror use previouse value.