Win10 laptop suddenly refusing SMB1 connections

Something has happened to my laptop (running Windows 10) such that Android apps using SMB1 protocol can no longer connect to it. When I try to access the laptop from the Android ES File Explorer app, ES reports "The server that you want to set up requires SMB2.0...". ES gives an option to enable SMB2 but that's no use to me. I need to be able to access this computer from other Android apps that don't have SMB2 support (specifically the Android app I am currently developing).

I can still connect to my other Windows 10 box (tower machine) and my Seagate NAS drive without problem.

It was all working fine a week or so back. I haven't knowingly made any configuration changes in the interim but I did notice that the laptop's Workgroup setting reverted to "Workgroup" (which I subsequently changed back) so I'm guessing there's been some sort of automatic Windows update.

I have tried various remedies I found on the web and nothing has worked. Under "Programs and features", "Windows features", the option "SMB 1.0/CIFS File Sharing Support" is checked. I have tried putting an explicit DWORD SMB1=1 in HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer
\Parameters. Most recently, I tried the following commands I found in a TechNibble article:

sc.exe config lanmanworkstation depend= bowser/mrxsmb10/mrxsmb20/nsi
sc.exe config mrxsmb10 start= auto
sc.exe config mrxsmb20 start= auto
reg add HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters /v SMB1 /t REG_DWORD /d 1 /f
reg add HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters /v SMB2 /t REG_DWORD /d 1 /f
powershell set-smbserverconfiguration -enablesmb1protocol $true
powershell set-smbserverconfiguration -enablesmb2protocol $true

Then rebooted. All to no avail. The laptop remains obstinately listed as "requiring SMB2" according to ES File Explorer, and other Android apps are unable to access it at all.

There's a secondary, minor, problem that started happening at the same time. I only mention it in case it's relevant. Before I had this problem, my Android apps were able to access all Windows shares by server name. Now, I can only access my tower PC and my NAS drive by explicit IP address. The translation of server name to IP seems to have stopped working for Android apps at the same time. Note that's only for Android apps. My Windows PCs can still find and access each other (and the NAS) by name.

Any suggestions why my laptop, and only my laptop, is now being listed as requiring SMB2 when it was working fine a week or so back? Any other diagnostics I can perform to determine whether SMB1 really is enabled? All help and advice gratefully received.

Regards
Keith

Rumour has it that SMB1 may be removed in the Fall Creators Update. It was after all the vector by which Wannacry was spread.

I was worried that removing SMB1 may affect my ability to connect to shares on my router, but checking my 15063.540 system with smbserverconfiguration shows it's already turned off (not by me, so probably by a recent update).

bro67 said:

SMBv1 has been disabled for a while in Android, Linux, Mac OS, because it is out dated and also is a huge security risk, which caused systems to be infected with Wanna cry and the last system wiper. The latest updates for Android should be forcing SMBv2 now.

I don't really understand what you mean by disabled in Android. So far as I'm aware, Android itself doesn't offer any facilities to access network shares via SMB. It's all done by third party apps, usually using standard libraries, nearly all of which are currently SMB1. I don't see how Android could force SMB2. Also, in the Android world, the vast majority of devices are not using the latest version. They are normally locked onto whatever version the manufacturer pre-installed and aren't updatable unless rooted (which most lay users won't do).

For my app, I'm not too worried about security issues as it's designed to be used in a closed environment; just one PC and a dozen Android tablets connected by a WiFi router that has no onward connection to the internet.

I have managed to find an SMB2 library that I could use in my app but it's still under development and the programmatic interface is significantly different from the SMB1 library I'm currently using. It's therefore not a trivial task to convert and I'd rather complete my testing with the current library and leave SMB2 for a later release. As I said, my other Win10 box is still reachable using SMB1 so there must be some way I can get my laptop back to that state.

bro67 said:

No rumor about it. It is supposed to be gone, along with a lot of other legacy stuff. IE is supposed to also get pulled, even though you can always load it if you need it as a backup.

My Synology NAS has not has SMBv1 capabilities for some time. You can force it in SMB advanced, but it gets firewalled.

But, unfortunately, the Android world hasn't really caught up with this. SMB2 libraries available for app developers like myself to use are only just starting to appear and most legacy apps seem to be SMB1 only.

As I said in a previous post, security isn't an issue for me. Until recently, I had two Win10 boxes happily accepting SMB1 connections. I still have one. I just want to undo whatever happened to the other box so I can carry on with my testing. I assume there's an option to roll-back Windows updates?

swarfega said:

I would avoid using SMB1, its very insecure.

In an ideal world, I would agree but I don't really have that option in the short term. Also, I don't perceive any great danger in a network environment that is isolated from the outside world.

bro67 said:

Yes there is an option. Keep using SMBv2, since Google does not allow SMBv1 to be used with the OS. I have had zero problems with ES on my NVIDIA shield, Matricom box or Google Pixel, when it comes to connecting to my Synology NAS through FTP.

This is getting silly. To "keep" using SMB2 is not an option for me. What ES does or does not do is irrelevant. I am talking about my app that I am developing. Much as I would like to move to SMB2, the SMB libraries shipped with Android Studio were, unfortunately, SMB1 and that is what I developed against. I have recently found some SMB2 libraries but the interface is different and I don't have the time or resources to upgrade my app to SMB2 at this time. It was working perfectly well talking to both my laptop and my tower PC a week or so ago. Now it only works talking to the tower PC. I just want to get my laptop back to where it was.

These philosophical discussions as to whether one should, or should not, use SMB1 are very interesting and I have learned a lot from them but the bottom line is that I want to complete my testing so that my bridge club (who are the end user) can start using the scoring system. To do that, I need my laptop to accept an SMB1 connection. As I said before, the network upon which it is ultimately to be used is closed off from the outside world so I don't forsee any security threats. Once I've got the initial version up and running then, and only then, might I have time to look into upgrading it to use SMB2. As for Google/Android enforcing SMB2, that's a non issue so far as I am concerned. The version of Android in use on our kit is an old one that patently does permit SMB1 and that is unlikely to change in the near future, if ever.

So can we please put aside issues of whether I should, or should not, be using SMB1 and just accept the fact that, rightly or wrongly, that is what I wish to do. That said, can anyone now help me with my original question. What might have happened to my laptop to cause it to appear to Android as requiring SMB2 and is there any way to reverse that change?