Difficulties opening PDF/Office files stored on Mac 'server' with a Windows PC

A customer has a Yosemite iMac that she uses to share files with a colleague (also a Mac user) at a second office.  They had let the AFP port open on the router but we have secured this and they now use a VPN to access the files – all works well.

She wanted to give access to another colleague in a third office, so we set up another remote account on the iMac. But nothing we did would allow this user to gain access to the files. After much head-scratching we discovered that the first remote user had been setup when the iMac had been running Lion Server and the iMac has been upgraded with all of the OSX variations right up to Yosemite. The server elements weren't working properly.

We downloaded & installed the Server App for Yosemite, set up this second remote user and now the user can access the folders that have been shared specifically for her.

We successfully tested this on a Mac only to find out that the second remote user actually uses Win7 on a PC and she has the following issues:
When she tries to open a PDF file, Adobe reader reports that “there was an error opening this document. The file is already open or in use by another application”.  It isn’t open or in use. We can copy it from the iMac to the PC and open it fine. We can save it back onto the iMac but it still won’t open directly on her PC from the Mac.

Similarly Word/Excel files report that they’re locked for editing by ‘another user’, even though they aren’t.

If we open the same files on a remote Mac, we don’t experience any of the locked file issues, so I think it’s something to do with the Mac/Win combination.  I can imagine why Word/Excel might complain but having difficulty just trying to open a PDF file is strange.  

All locations are running fibre broadband with an average of 10Mbps/4Mbps down/up, so I don’t think speed over the VPN is a problem.  
We don’t know enough about Mac Server to start dabbling.  Can anyone point me in the right direction?

Thanks, Ian
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Davis McCarnOwnerCommented:
I smell a permissions issue.  On the hosting Mac, you should inspect the permissions for the user that works and then for the user that doesn't.
On OS X, its also highly recommended that you use the disk utility and verify/repair the permissions at least once every six months.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
blueskycomputingAuthor Commented:
Thanks Davis but I doubt it's permissions as we can log in on a Mac as the same troubled user and have no problems opening or saving files, only when we do this from any WIndows PC across the VPN (we can't easily test a Windows PC on the LAN).  We'll carry out a verify/repair anyway and will let you know the outcome.
I've requested that this question be deleted for the following reason:

Not enough information to confirm an answer.
blueskycomputingAuthor Commented:
Repeated repairing seemed to fix this in the end - it took 3 or 4 goes. Apologies for not responding sooner.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Windows Networking

From novice to tech pro — start learning today.