LastPass password manager

I hope I’m in the right place…this is new for me. Firefox just had a recent update that, I understand, will no longer be compatible with LastPass password manager. Is this true and, if so, will there be a fix for it? I’m paying for that software and don’t want to cancel it or change web browsers.

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Thanks again to @amyt and colleagues.

Beta 4.2.0a was released on 2017-10-12 and is:

  • compatible with e.g. Firefox 56.0.1
  • not compatible with Firefox 57.

Another beta, announced on the same day:

  • has a version number that’s inferior ( at the time of writing)
  • is described by LastPass as for Firefox 57
  • is also compatible with Firefox 56.0.1:

(Ignore the 1970 date in that screenshot. It’s a cosmetic bug, unrelated to LastPass.)

From manifest.json:

			"strict_min_version": "52.0",
			"update_url": ""

– but I do not intend to test with any 52.x extended support release (ESR).

For reference only:

LastPass: Free Password Manager installed, disappeared, worked around by a quit from Firefox 56.x.

LastPass Premium support ticket:

  • 6308242

From the foot of my report to LastPass:

… doubt that we’ll make this issue reproducible.

It reminds me of LastPass ticket 6101942, where Xmarks Bookmarks Sync was inexplicably absent and nonfunctional whilst installed.

From my most recent comment in the ticket:

… With an assumption that the bug will not recur, I’m happy for this ticket to be closed. With the user community and developers in mind: if you receive comparable reports from other users, please feel free to reopen here, or ping me in the topic at Mozilla Discourse. …

(6101942 was partially discussed under Xmarks Bookmarks Sync (previously known as Xmarks Sync) allowing multiprocess (e10s) and using WebExtensions APIs - Add-ons / Add-on Support - Mozilla Discourse.)

Blank page when aiming to edit with

For example, where
is the result of using the LastPass button to find then edit a matching site.

Reproducible with Firefox 57.x?

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The LastPass - Upgrade page (captured in the Wayback Machine) is slightly mistaken in its timeline:

  • truly, 4.2.0a was released on the same day as (not four days later).

The beta for 57, with 52

Yesterday for the first time I launched Firefox ESR (64-bit) 52.4.1 in 32-bit mode on an old Mac. Whilst the session was not primarily for LastPass, I did take the opportunity to add LastPass beta for Firefox 57 to Firefox 52.

My next use of the Mac will probably be to profile an extension-related performance issue (Quantum Flow). The affected extension is not any version of LastPass, but I might take the opportunity to follow up with some proper testing of the beta for 57, with 52 …

… beginning with the blank page symptom mentioned in my previous post.

Problems with the first Firefox Quantum-compatible release

Post-update: attention is drawn to However the loss of functionality with the first Firefox 57-compatible release is broader than the shortlist associated with binary components.


Compatibility with modal dialogues such as this:

Legacy versions 4.1.67 and are compatible:

  • LastPass can fill the fields.

(Screenshot: with Firefox 56.0.2 (64-bit) on FreeBSD-CURRENT.)

2017-11-09 release is not compatible. I have made LastPass Support aware through a tweet.

LastPass premium support ticket # 6529225

LastPass is not compatible with modal authentication dialogues in Firefox 56.0.2.

Please see:

a) outdated captured at

b) with reference to the shortlist at – no mention of authentication dialogues in that list

c) my screenshot at

… Legacy versions 4.1.67 and are compatible:

  • LastPass can fill the fields.

… Firefox 56.0.2 (64-bit) on FreeBSD-CURRENT. …

… is not compatible. …

Whilst I have not yet tested with Firefox ESR 52.5.0 – scheduled for released by Mozilla 2017-11-14 (ported to FreeBSD 2017-11-11) – I expect to find comparable loss of functionality with the update to

It seems to me that:

a) provision of to users of 52.x and 56.x is premature (modal authentication dialogues are commonplace, and so on); and

b) we have multiple problems with documentation (with rushes by developers in various areas – not LastPass alone – to make things compatible with Firefox Quantum).

Focusing on compatible legacy versions for Firefox:

  • please, can someone at LastPass summarise the differences between release 4.1.67 and alpha


There’s same problem – loss of integration with modal authentication dialogues – with and 4.2.4a on Waterfox 56.0.3_2.

Legacy is preferred – it does not suffer from the regression.

The same problem – loss of integration – with on Firefox 57.0.4 on build 16G1210 of Mac OS X 10.12.6.

Do WebExtensions APIs – in 57.x – not include what’s required?

Steps to reproduce the bug

  1. save dummy credentials for e.g.:

  1. visit


  • integration – both fields automatically filled:

2018-01-19 06:01:37

Actual result

  • no integration:

2018-01-19 06:03:43

I’d like to test 58.x on the Mac but it stops responding before any page can load, useless for testing.

LastPass 4.9.0 has, in its manifests.json:

"strict_min_version": "52.0"

– but it’s unusable with Firefox ESR 52.7.3:

(Similarly unusable with Waterfox 56.1.0_1.)

Could/should that type of incompatibility be caught through automation?


Generally not. It’s very hard to analyze code automatically, especially given all the ways in which APIs can be used.

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Thanks, understood.

Testing last week’s version 4.9.0 with Firefox Nightly 61.0a1 (2018-04-06) (64-bit) on build 16G1404 of Mac OS X 10.12.6.

Still without the integration that’s a feature of legacy

What’s up?

If the feature is blocked by Mozilla bugs, please can you let us have the numbers?


I don’t know enough about LastPass to comment on that. You would need to bring it up to them.

Thanks, I raised the issue five months ago (premium support request #6529225), closed without explanation, I have asked for the issue to be reopened, still pending.

Don’t take it personally, but I feel like there’s a wall of silence following closure of … with so many users of the extension – not least, people within Mozilla – I can’t believe that this loss of functionality with modal authentication dialogues wasn’t known before closure.

Firefox 59.0.3 here, get the same blank page. Errors in the console are CSS-related only. on Firefox 60.0,1: no longer reproducible.

Interesting, I just switched to FF 60.0 and have LP 4.9.2 and the problem persists. Trying to edit a LP entry from the addon brings up the moz-extension://[…] page but blank for me.

Join me in I’m now using slightly greater version 60.0_1,1 of Firefox (on FreeBSD-CURRENT) and issues with LastPass seem to be transient.