When copying from or to external drive

[Schmunzel57]

When i copy or move a file from or to an external Drive USB3.0 i get the Error. Not when i use only external Drives USB2.0. Then i read the following Topic "Writing to 4tb external hard drives" in this forum. After i turn off the setting "Automatically detect read/write strategy for file copy" i get no Error. But before the end of the operation (copy and move) there is a break for a few seconds before the operation comes to an positiv end.
Is there any problem with external drives USB3.0 ?

[Mathias (Author)]

This is how windows works.

When you activate that option that everything goes through the windows read/write cache.
And when writing to a target that Windows is using the cache on, a write request is completed as soon as the data is written to the cache, not the drive.
And since writing to cache is a lot faster then writing to drive the cache fills up faster. and when the cache is full a write request is blocked and wait until Windows is done written enough data to the drive and frees up some cache.
You can also get a block/wait when a file is closed when the write is complete. and that is because of the same reason. Windows decided to block until the data in the cache is written to the disk before you can continue.
Windows is extra careful with USB devices (or any removable device) and makes sure to flush new data for them more aggressively so that if you just pull out the drive after a copy you should not lose anything..  That is why you should do safe removal on removable drives that you have written to,  in case there are unflushed data in write caches that needs to be written before the drive is removed.