Provided the backup has all of your bookmarks that you need, there's no issue. It's likely that Firefox has just compressed the file a little better than the original backup or that the newer versions of Firefox store less unwanted information in the backup file.

Wesley Branton said there are alot missing. 173 backup was created using Jan 6th's latest (64.0.2) and the current Firefox (65.0.1) is latest.And there are no changes in compression of html between these releases.

Those files seem rather large; my bookmarks.html export file size is only 5.1MB.

Have you tried a text comparison tool such as http://winmerge.org/ to see whether you can find the differences?

Note that favicon data (ICON) can take up a lot of space in an HTML backup.

As usual with this user, he has a very similar thread over here - https://support.mozilla.org/en-US/questions/1251194 - that was started just a few days ago. It has an answer about bookmarks.HTML and the size difference regarding the Favicons images.

jscher2000 said

Those files .... differences?

I have a lot of bookmarks 20000+

cor-el said I have a lot of bookmarks around 10000.Icons are larger than text and when having 1000s of bookmarks it becomes more clear.

the-edmeister said No, both question are different In this I am asking is there any problem with importing or exporting of html backups.(Import from firefox after exporting 173mb is 60mb) And in the other question I am asking is there any problem with firefox sync.(Import from firefox sync is 8mbs)

RexaFire said

jscher2000 said

Those files seem rather large; my bookmarks.html export file size is only 5.1MB. Have you tried a text comparison tool such as http://winmerge.org/ to see whether you can find the differences?

I have a lot of bookmarks around 10000. Compressing will just make the ratio 173:8 to 100:10, problem is not that.

Try the text comparison tool if it can handle the files.

jscher2000 said There are 4873 differences in 173mb backup and Backup taken after Importing .I used WinMerge.

RexaFire said

There are 4873 differences in 173mb backup and Backup taken after Importing .I used WinMerge.

And if you skim through them, where are the differences, can you characterize them as particular types of data?

jscher2000 said There are many red blocks(group of lines). Every line is a bookmark.

And when you compare the lines flagged as different by the tool, can you find the differences between the same bookmarks in the two files?

jscher2000 said Mostly, complete lines are missing.

So for example, you compare the same folder in both files and in one of the files, some bookmarks are missing?

jscher2000 said Yes exactly , bookmarks are missing from the backup taken by exporting (60Mb Backup).

And yet another thread about this dilemma started here: https://support.mozilla.org/en-US/questions/1252149

This could help identify the problem.