How can I get USB disk to work reliably in Mac OS and in Windows under Parallels?

I run Parallels on an iMac and have reliability issues with USB sticks.

I need to copy files to and from the USB stick so as to use them on my Toshiba Ultrabook running Windows.

I find that it works well for a while then over time either Mac OS or Windows on the Mac won’t recognise the disk or else will start running extremely slowly in Windows Explorer.

As a result I have replaced quite a few USB disks and eventually ended up in the same position.

Recently I bought a SanDisk USB disk from a Mac shop, I then copied files on to it in Windows Explorer under Parallels, put it into my Toshiba, copied some files back and forth, and when I put the USB back into the Mac , Windows (under Parallels) would not recognise it as it had just already done.

Usually I find when putting USB sticks into the Mac the system will ask me if I want to connect it under Mac OS or under Windows and previously I found that choosing Mac gave me access under both anyway.

With this new USB the only way to get it to be recognised under Windows was to choose Windows when connecting then I could read it in Window Explorer, but not in Mac OS of course.

Has anyone any ideas please?  

The change in behaviour over time (recognising, then not recognising, and/or slowing right down) is a great frustration.

Thankyou for your assistance.
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.

What format is the old USB stick?  What format is the new USB sitck?

Select the USB and right click to open the popup menu, then Select Get Info.  You can also do a command i to Get Info.

Expand the General section to check the Format.

Have you tried Disk Utility to reformat the USB stick?

Have you also though about just sharing your folders and copying files directly over network?  I suggest using a wired network for faster consistent speeds if you still have slower Wifi.
I traditionally format my USB sticks in FAT32 common file format so it can be read via multiple platforms.  I do the formatting on a PC so that it is a true format.
FAT32 is obsolete and not worthwhile.  EXFAT is little better if you do share it between OSes frequently.

For larger sizes of USB, I format it NTFS, if the main shared systems are going to be Windows, and HFS+, if the main shared systems are Mac.  There are advantages to using a native format.  There are free applications to read and write the other format on both systems and I'd rather install those on the outnumbered systems.  It saves quite a bit of trouble.
Determine the Perfect Price for Your IT Services

Do you wonder if your IT business is truly profitable or if you should raise your prices? Learn how to calculate your overhead burden with our free interactive tool and use it to determine the right price for your IT services. Download your free eBook now!

Glen_SydneyAuthor Commented:
Thankyou for your various advice and sorry for the delay replying.

I will investigate the formatting options and get back to you.

I also realised both my Mac OS and Parallels are one version behind the latest version, not sure if that has any impact, but I do intend to upgrade both shortly.
Those have no relevance to the file system on your USB memory stick.
Glen_SydneyAuthor Commented:
Thankyou for that.   I tried formatting a USB in the Mac Disk Utility but could not find NTFS, so I tried EXFAT but of course it won't read under Mac OS now.

I tried formatting it in NTFS on my Toshiba Ultrabook but could not work how to format it.   Where do I do that in Windows please?

Thanks again.
EXFAT should have been readable in OS X.

To format in Windows, you can right-click on your Computer and select Manage.  When the Computer Management console starts Select Disk or Storage depending on your version of Windows.  Choose Disk Management.  You might be able to just search for Disk Management and just start that portion only.  You should then be able to partition, label and format your disk.
Glen_SydneyAuthor Commented:
Thankyou, I will try that and let you know how it goes.   :-)
Glen_SydneyAuthor Commented:
Thankyou for your assistance and sorry for the delayed response.

What I have found is that accepting the USB stick under Windows in Parallels enables me to work with the files in Windows on the iMac and then also read it on the Toshiba laptop that I use.

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
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
Mac OS X

From novice to tech pro — start learning today.